(online hypertext link) (HTML/ON) The utility's form does not have to be used. By supplying the appropriate query string components, either from a custom form or forms, or directly embedded into links, profiles, listings, deletion may be generated. Cache directory trees have the potential to become heavily populated, so the use of the script to generate listings of the cache contents could return extremely large listing documents. (CONNECT Serving\hd_proxy_connect_serving)

The (connect) service provides firewall proxying for any connection-oriented TCP/IP access. Essentially it provides the ability to tunnel any other protocol via a Web proxy server. In the context of Web services it is most commonly used to provide firewall-transparent access for Secure Sockets Layer (SSL) transactions. It is a special case of the more general tunneling provided by WASD, see (hd_proxy_tunneling). (Enabling CONNECT Serving\hd_proxy_connect_enabling)

As with proxy serving in general, CONNECT serving may enabled on a per-service basis using the WASD_CONFIG_GLOBAL [service] directive, the WASD_CONFIG_SERVICE configuration file, or even the /SERVICE= qualifier.

The actual services providing the CONNECT access (i.e. the host and port) are specified on a per-service basis. This means it is possible to have CONNECT and non-CONNECT services deployed on the one server, as part of a general proxy service or standalone. CONNECT proxying is enabled by appending the (connect) keyword to the particular service specification. The following example shows a non-proxy and proxy services, with and without additional connect processing enabled. [[http://alpha.example.com:80]] [[http://alpha.example.com:8080]] [ServiceProxy] enabled [[http://alpha.example.com:8081]] [ServiceProxyTunnel] connect [[http://alpha.example.com:8082]] [ServiceProxy] enabled [ServiceProxyTunnel] connect (Controlling CONNECT Serving\hd_proxy_connect_control)

The connect service poses a significant security dilemma when in use in a firewalled environment. Once a CONNECT service connection has been accepted and established it essentially acts as a relay to whatever data is passed through it. Therefore (any transaction whatsoever\BOLD) can occur via the connect service, which in many environments may be considered undesirable.

In the context of the Web and the use of the connect service for proxying SSL transactions it may be well considered to restrict possible connections to the well-known SSL port, 443. This may be done using conditional directives, as in the following example: [[alpha.example.com:8080]] if (request-method:CONNECT) pass *:443 pass * "403 CONNECT only allowed to port 443." endif All of the comments on the use of general and conditional mapping made in (hd_proxy_control) can also be applied to the connect service. (FTP Proxy Serving\hd_proxy_ftp_serving)

WASD provides a proxy service for the FTP scheme (prototcol). This provides the facility to list directories on the remote FTP server, download and upload files.

The (probable) file system of the FTP server host is determined by examining the results of an FTP PWD command. If it returns a current working directory specification containing a (/) then it assumes it to be Unix(-like), if (:[) then VMS, if a () then DOS. (Some DOS-based FTP servers respond with a Unix-like (/) so a second level of file-system determination is undertaken with the first entry of the actual listing.) Anything else is unknown and reported as such. WASD (for the obvious reason) is particularly careful to perform well with FTP servers responding with VMS file specifications.

Note that the content-type of the transfer is determined by the way the proxy server interprets the FTP request path's (file) extension. This may or may not correspond with what the remote system might consider the file type to be. The default content-type for unknown file types is (application/octet-stream) (binary). When using the (alt) query string parameters then for any file in a listing the icon provides an alternate content-type. If the file link provides a text document then the icon will provide a binary file. If the link returns a binary file then the icon will return a file with a plain-text content-type.

In addition to content-type the FTP mode in which the file transfer occurs can be determined by either of two conditions. It the content-type is (text/..) then the transfer mode will be ASCII (i.e. record carriage-control adjusted between systems). If not text then the file is transfered in Image mode (i.e. a binary, opaque octet-stream). For any given content-type this default behaviour may be adjusted using the [AddType] directive (see (HREF=[-.config]config.sdml!../config/#hd_config_directives_alpha)([-.CONFIG]DOC_config.sdml)) or the (#!+) MIME.TYPES directive (see (HREF=[-.config]config.sdml!../config/#hd_config_content_mimetypes)([-.CONFIG]DOC_config.sdml)).

Rules required in WASD_CONFIG_MAP for mapping FTP proxy. This is preferably made against the virtual service providing the FTP proxy. The service explicitly must make the icon path used available or it must be available to the proxy service in some other part of the mappings. Also the general requirement for error message URLs applies to FTP proxying ((hd_proxy_error_messages)). [[proxy.host.name:8080] pass http://* http://* pass ftp://* ftp://* pass /*/-/* /wasd_root/runtime/*/* (FTP Query String Keywords\hd_proxy_ftp_query)

Keywords added to an FTP request query string allow the basic FTP action to be somewhat tailored. These case-insensitive keywords can be in the form of a query keys or query form fields and values. This allows considerable flexibility in how they are supplied, allowing easy use from a browser URL field or for inclusion as form fields.

((FTP Query String Keywords\BOLD)) (2\10) (Keyword\Description) (alt\Adds alternate access (complementary content-type at the icon) for directory listings.) (ascii\Force the file transfer type to be done as ASCII (i.e. with carriage-control conversion between systems with different representations).) (content\Explicitly specify the content type for the returned file (e.g. (content:text/plain), or (content=image/gif)).) (dos\When generating a directory listing force the interpretation to be DOS.) (email\Explicitly specify the (anonymous) access email address (e.g. (email:daniel@wasd.vsm.com.au) or (email=daniel@wasd.vsm.com.au)).) (image\Force the file transfer type to be done as an opaque binary stream of octets.) (list\Displays the actual directory plain-text listing returned by the remote FTP server. Can be used for problem analysis.) (login\Results in the server prompting for a username and password pair that are then used as the login credentials on the remote FTP server.) (octet\Force the content-type of the file returned to be specified as "application/octet-stream".) (text\Force the content-type of the file returned to be specified as "text/plain".) (unix\When generating a directory listing force the interpretation to be Unix.) (upload\Causes the server to return a simple file transfer form allowing the upload of a file from the local system to the remote FTP server.) (vms\When generating a directory listing force the interpretation to be VMS.) ((login) Keyword\hd_proxy_ftp_login)

The usual mechanism for supplying the username and password for access to a non-anonymous proxied FTP server area is to place it as part of the request line (i.e. (ftp://username:password@the.host.name/path/)). This has the obvious disadvantage that it's there for all and sundry to see.

The (login) query string is provided to work around the more obvious of these issues, having the authentication credentials as part of the request URL. When this string is placed in the request query string the FTP proxy requests the browser to prompt for authentication (i.e. returns a 401 status). When request header authentication data is present it uses this as the remote FTP server username and password. Hence the remote username and password never need to appear in plain-text on screen or in server logs. (Gatewaying Using Proxy\hd_proxy_gatewaying)

WASD is fully capable of mapping non-proxy into proxy requests, with various limitations on effectiveness considering the nature of what is being performed.

Gatewaying between request schemes (protocols) (SIMPLE) HTTP to HTTP (a gateway (of sorts) - standard proxy) HTTP TO HTTP-over-SSL (non-secure to secure) HTTP to FTP HTTP-over-SSL to HTTP (secure to non-secure) HTTP-over-SSL to HTTP-over-SSL (secure to secure) HTTP-over-SSL to FTP

and also gatewaying between IP versions (SIMPLE) IPv4 to IPv6 IPv6 to IPv4

All can be useful for various reasons. One example might be where a script is required to obtain a resource from a secure server via SSL. The script can either be made SSL-aware, sometimes a not insignificant undertaking, or it can use standard HTTP to the proxy and have that access the required server via SSL. Another example might be accessing an internal HTTP resource from an external browser securely, with SSL being used from the browser to the proxy server, which the accesses the internal HTTP resource on its behalf. (Request Redirect\hd_non_proxy_redirect)

The basic mechanism allowing this gatewaying is (internal) redirection. The (redirect) mapping rule (see (HREF=[-.config]config.sdml!../config/#hd_map_rule_redirect)([-.CONFIG]DOC_config.sdml)) either returns the new URL to the originating client (requiring it to reinitiate the request) or begins reprocessing the request internally (transparently to the client). It is this latter function that is obviously used for gatewaying. (Reverse Proxy\hd_non_proxy_reverse)

The use of WASD proxy serving as a firewall component assumes two configured network interfaces on the system, one of which is connected to the internal network, the other to the external network. (Firewalling could also be accomplished using a single network interface with router blocking external access to all but the server system.) Outgoing (internal to external) proxying is the most common configuration, however a proxy server can also be used to provide controlled external access to selected internal resources. This is sometimes known as (reverse proxy) and is a specific example of WASD's general (non-proxy to proxy) request redirection capability ((hd_proxy_gatewaying)).

In this configuration the proxy server is contacted by an external browser with a standard HTTP request. Proxy server rules map this request onto a proxy-request format result. For example: redirect /sales/* /http://sales.server.com/*?

Note that the trailing question-mark is required to propagate any query string (see (HREF=[-.config]config.sdml!../config/#hd_map_rule_redirect)([-.CONFIG]DOC_config.sdml)).

The server recognises the result format and performs a proxy request to a system on the internal network. Note that the mappings required could become quite complex, but it is possible. See example 7 in (hd_proxy_control). (Redirection Location Field\hd_non_proxy_reverse_302)

If a reverse proxied server returns a redirection response (302) containing a (Location: (url)) field with the host component the same reverse-proxied-to server it can be rewritten to instead contain the proxy server host. If these do not match the rewrite does not occur. Using the redirection example above, the SET mapping rule (proxy=reverse=location) specifies the path that will be prefixed to the path component in the location field URL. Usually this would be the same path used to map the reverse proxy redirect (in this example (/sales/)), though could be any string (presumably detected and processed by some other part of the mapping). set /sales/* proxy=reverse=location=/sales/ redirect /sales/* /http://sales.server.com/*? This could be simplified a little by using a postfix SET rule along with the original redirect. redirect /sales/* /http://sales.server.com/*? proxy=reverse=location=/sales/

If the (proxy=reverse=location=()) ends in an asterisk the entire 302 location field URL is appended (rather than just the path) resulting in something along the lines of Location: http://proxy.server.com/sales/http://sales.server.com/path/ which once redirected by the client can be subsequently tested for and some action made by the proxy server according to the content (just a bell or whistle ;-). (Authorization Verification\hd_non_proxy_reverse_verify)

WASD can authorize reverse proxy requests locally (perhaps from the SYSUAF) and rewrite that username into the proxied requests (Authorization: ) field. The proxied-to server can then verify that the request originated from the proxy server and extract and use that username as authenticated.

This functionality is described in the (HTML= WASD_ROOT:[SRC.HTTPD]PROXYVERIFY.C ) (HTML/OFF) WASD_ROOT:[SRC.HTTPD]PROXYVERIFY.C (HTML/ON) module. (proxyMUNGE Utility\hd_non_proxy_munge)

This utility (CGIplus script) can be used to rewrite HTTP response (Location:) fields, (Set-Cookie:) path and domain components and URLs in HTML and CSS content.

This functionality is described in the prologue to the code (HTML= WASD_ROOT:[SRC.UTILS]PROXYMUNGE.C ) (HTML/OFF) WASD_ROOT:[SRC.UTILS]PROXYMUNGE.C (HTML/ON) The proxyMUNGE Utility handles all response rewriting and so when employing it to perform reverse-proxy processing it is unnecessary to use the (proxy=reverse=location=()) mapping rule described in (hd_non_proxy_reverse_302). (One-Shot Proxy\hd_non_proxy_one_shot)

This looks a little like reverse proxy, providing access to a non-local resource via a standard (non-proxy) request. The difference allows the client to determine which remote resource is accessed. This works quite effectively for non-HTML resources (e.g. image, binary files, etc.) but non-self-referential links in HTML documents will generally be inaccessible to the client. This can provide provide scripts access to protocols they do not support, as with HTTP to FTP, HTTP to HTTP-over-SSL, etc.

Mappings appropriate to the protocols to be support must be made against the proxy service. Of course mapping rules may also be used to control whom or to what is connected. [[the.proxy.service:port]] # support "one-shot" non-proxy to proxy redirect redirect /http://* http://* redirect /https://* https://* redirect /ftp://* ftp://* # OK to process these (already, or now) proxy format requests pass http://* http://* pass https://* https://* pass ftp://* ftp://*

The client may the provide the desired URL as the path of the request to the proxy service. Notice that the scheme provided in the desired URL can be any supported by the service and its mappings. http://the.proxy.service:port/http://the.remote.host/path http://the.proxy.service:port/https://the.remote.host/path http://the.proxy.service:port/ftp://the.remote.host/pub/ (DNS Wildcard Proxy\hd_non_proxy_dns_wildcard)

This relies on being able to manipulate host record in the DNS or local name resolution database. If a (*.the.proxy.host) DNS (CNAME) record is resolved it allows any host name ending in (.the.proxy.host) to be resolved to the corresponding IP address. Similarly (at least the Compaq TCP/IP Services) the local host database allows an alias like (another.host.name.proxy.host.name) for the proxy host name. Both of these would allow a browser to access (another.host.name.proxy.host.name) with it resolved to the proxy service. The request (Host:) field would contain (another.host.name.proxy.host.name).

Using this approach a fully functioning proxy may be implemented for the browser without actually configuring it for proxy access, where returned HTML documents contain links that are always correct with reference to the host used to request them. This allows the client an (ad hoc) proxy for selected requests. For a wildcard (CNAME) record the browser user may enter any host name prepended to the proxy service host name and port and have the request proxied to that host name. Entering the following URL into the browser location field http://the.host.name.the.proxy.service:8080/path would result in a standard HTTP proxy request for (/path) being made to (the.host.name:80). With the URL https://the.host.name.the.proxy.service:8443/path an SSL proxy request. Note that normally the well-known port would be used to connect to (80 for http: and 443 for https:). If the final, period-separated component of the wildcard host name is all digits it is interpreted as a specific port to connect to. The example http://the.host.name.8001.the.proxy.service:8080/path would connect to (the.host.name:8001), and https://the.host.name.8443.the.proxy.service:8443/path to (the.host.name:8443). It has been observed that some browsers insist that an all-digit host name element is a port number despite it being prefixed by a period not a colon. These browsers then attempt to contact the host/port directly. This obviously precludes using an all-digit element to indicate a target port number with these browsers.

This wildcard DNS entry approach is a more fully functional analogue to common proxy behaviour but is slightly less flexible in providing gatewaying between protocols and does require more care in configuration. It also relies on the contents of the request (Host:) field to provide mapping information (which generally is not a problem with modern browsers). The mappings must be performed in two parts, the first to handle the wildcard DNS entry, the second is the fairly standard rule(s) providing access for proxy processing. [[the.proxy.service:port1]] if (host:*.the.proxy.service:port1) redirect * /http://* else pass http://* http://* endif

The obvious difference between this and one-shot proxy is the desired host name is provided as part of the URL host, not part of the request path. This allows the browser to correctly resolve HTML links etc. It is less flexible because a different proxy service needs to be provided for each protocol mapping. Therefore, to allow HTTP to HTTP-over-SSL proxy gatewaying another service and mapping would be required. [[the.proxy.service:port2]] if (host:*.the.proxy.service:port2) redirect * /https://* else pass https://* https://* endif (Originating SSL\hd_proxy_gateway_ssl)

This proxy function allows standard HTTP clients to connect to Secure Sockets Layer ((cr_ssl)) services. This is very different to the CONNECT service ((hd_proxy_connect_serving)), allowing scripts and standard character-cell browsers supporting only HTTP to access secure services.

Standard username/password authentication is supported (as are all other standard HTTP request/response interactions). The use of X.509 client certificates ((hd_ssl_x509_auth)) to establish outgoing identity is not currently supported. (Enabling SSL\hd_proxy_gateway_ssl_enabling)

Unlike HTTP and FTP proxy it requires the service to be specifically configured using the [ServiceClientSSL] directive.

There are a number of Secure Sockets Layer related service parameters that should also be considered (see (HREF=[-.config]config.sdml!../config/#cr_service_directives)([-.CONFIG]DOC_config.sdml)). Although most have workable defaults unless [ServiceProxyClientSSLverifyCA] and [ServiceProxyClientSSLverifyCAfile] are specifically set the outgoing connection will be established without any checking of the remote server's certificate. This means the host's secure service could be considered unworthy of trust as the credentials have not been established. [[http://alpha.example.com:8080]] [ServiceProxy] enabled [ServiceClientSSL] enabled (Tunneling Using Proxy\hd_proxy_tunneling)

WASD supports the CONNECT method which effectively allows tunneling of raw octets through the proxy server. This facility is most commonly used to allow secure SSL connections to be established with hosts on the 'other side' of the proxy server. This basic mechanism is also used by WASD to provide an extended range of tunneling services. The term (raw) is used here to indicate an 8 bit, bidirectional, asynchronous exchange of octets between two entities, as a protocol family, not necessarily as an application (but can be so). Global proxy serving must be enabled ((hd_proxy_enabling)) and then each service must be configured and mapped according to the desired mode of tunneling. Disabling or setting timeouts appropriately on the mapped service is important if connections are not to be disrupted by general server timeouts on output and non-progress (quiescent connections). ([ServiceProxyTunnel] CONNECT\hd_proxy_tunneling_connect)

A service with this configuration is used as a target for CONNECT proxying (usually SSL through a firewall). The client expects an HTTP success (200) response once the remote connection is established, and HTTP error response if there is a problem, and once established just relays RAW octets through the proxy server (classic CONNECT behaviour). # WASD_CONFIG_SERVICE [[http://*:8080]] [ServiceProxy] enabled [ServiceProxyTunnel] connect # WASD_CONFIG_MAP [[*:8080]] if (request-method:connect) pass *:443 *:443 pass * "403 CONNECT only allowed to port 443." endif

This configuration enables CONNECT processing and limits any connect to SSL tunneling (i.e. port 443 on the remote system). ([ServiceProxyTunnel] RAW\hd_proxy_tunneling_raw)

This allows any raw octet client (e.g. telnet) to connect to the port and by mapping be tunnelled to another host and port to connect to its service (e.g. a telnet service). The usual HTTP responses associated with CONNECT processing are not provided. # WASD_CONFIG_SERVICE [[http://*:10023]] [ServiceProxy] enabled [ServiceProxyTunnel] raw # WASD_CONFIG_MAP [[*:10023]] if (request-method:connect) pass *:0 raw://another.host:23 timeout=none,none,none endif pass "403"

Telnet is used in the example above but the principle equally applies to any protocol that uses a raw 8 bit, bidirectional, asynchronous exchange of octets. Another example might be an SMTP service (port 25). (SSL to RAW\hd_proxy_tunneling_raw_tls)

Using a tunnel it is possible to put a TLS/SSL (https://) front-end service to an otherwise plaintext-only service (http://). # WASD_CONFIG_SERVICE [[https://tls-host:443]] [ServiceNonSSLRedirect] https://tls.host:443 [ServiceProxy] enabled [ServiceProxyTunnel] raw # WASD_CONFIG_MAP [[*:443]] if (request-method:connect) pass *:0 raw://non-tls.host:80 endif pass "403" (Chaining RAW\hd_proxy_tunneling_raw_chain)

It is possible to have a raw tunnel establish itself through a proxy chain ((hd_proxy_chaining)) by transparently generating an intermediate CONNECT request to the up-stream proxy server. Note that not all CONNECT proxy will allow connection to just any specified port. For security reasons it it is quite common to restrict CONNECT to port 443. # WASD_CONFIG_SERVICE [[http://*:10025]] [ServiceProxy] enabled [ServiceProxyTunnel] raw # WASD_CONFIG_MAP [[*:10025]] if (request-method:connect) pass *:0 raw://another.host:25 proxy=chain=proxy.host:8080 endif pass "403"

Any error in connecting to the chained proxy, making the request, connecting to the destination, etc. (i.e. any error at all) is not reported. The network connection is just dropped. Use WATCH to establish the cause if necessary. ([ServiceProxyTunnel] FIREWALL\hd_proxy_tunneling_firewall)

With this configuration a service expects that the first line of text from the client contains a host name (or IP address) and optional port (e.g. (the.host.name) or (the.host.name:23)). This allows a variable destination to be mapped. The usual HTTP responses associated with CONNECT processing are not provided. # WASD_CONFIG_SERVICE [[http://*:10023]] [ServiceProxy] enabled [ServiceProxyTunnel] FIREWALL # WASD_CONFIG_MAP [[*:10023]] if (request-method:connect) pass *:* raw://*:23 timeout=none,none,none pass * raw://*:23 timeout=none,none,none endif pass "403"

The pass rules force the supplied domain name (and optional port) to be mapped to the telnet port (23). Of course the mapping rules could allow the supplied port to be mapped into the destination if desired. (Chaining FIREWALL\hd_proxy_tunneling_raw_fire)

As with [ServiceProxyTunnel] RAW it is possible to chain FIREWALL services to an up-stream proxy server. See (hd_proxy_tunneling_raw_chain). (Encrypted Tunnel\hd_proxy_tunneling_encrypted)

Up to this point the tunnels have merely been through the proxy server. It is possible to establish and maintain ENCRYPTED TUNNELS between WASD servers. SSL is used for this purpose. This is slightly more complex as both ends of the tunnel need to be configured. (There is a leading (^H) two spaces in on the next line) () +------------+ +------------+ <-unencrypted->| WASD proxy |<-ENCRYPTED->| WASD proxy |<-unencrypted-> +------------+ +------------+

This arrangement may be used for any stream-oriented, network protocol between two WASD systems. As it uses standard CONNECT requests (over SSL) it MAY also be possible to be configured between WASD and non-WASD servers.

The following example is going to maintain an encrypted tunnel between WASD servers running on systems KLAATU and GORT. It is designed to allow a user on KLAATU to connect to a specified port using a telnet client, and have a telnet session created on GORT, tunnelled between the two systems via an SSL encrypted connection.

Source of tunnel: # KLAATU WASD_CONFIG_SERVICE [[http://*:10023]] [ServiceProxy] enabled [ServiceClientSSL] ENABLED [ServiceProxyTunnel] RAW # KLAATU WASD_CONFIG_MAP [[*:10023]] # if the client is on the local subnet if (remote-addr:192.168.0.0/24 && request-method:connect) pass *:0 https://gort.domain:10443 timeout=none,none,none endif pass "403"

Destination of tunnel: # GORT WASD_CONFIG_SERVICE [[https://*:10443]] [ServiceProxy] enabled [ServiceProxyTunnel] CONNECT # GORT WASD_CONFIG_MAP [[*:10443]] # limit the connection to a specific host if (remote-addr:192.168.0.10 && request-method:connect) pass *:0 raw://gort.domain:23 timeout=none,none,none endif pass "403"

When a client connects to the service provided by port 10023 on system KLAATU the connection is immediately processed using a pseudo CONNECT request header. The service on this port is a proxy allowed to initiate SSL connections (client SSL). This service is mapped to system GORT port 10443, an SSL service that allows the CONNECT method (tunneling). KLAATU's proxy initiates an SSL connection with GORT. When established and the CONNECT request from KLAATU is received, it is mapped via a raw tunnel (8 bit, etc.) to its own system port 23 (the telnet service). Telnet is in use at both ends while encrypted by SSL inbetween! Note the use of network addresses and general fail rules used to control access to this service, as well as the disabling of timers that might otherwise shutdown the tunnel. (Encrypted Tunnel With Authentication\hd_proxy_tunneling_auth)

This arrangement is essentially a variation on example 4. It provides a cryptographic authentication of the originator (source) of the tunnel.

Source of tunnel: # KLAATU WASD_CONFIG_SERVICE [[http://*:10023]] [ServiceProxy] enabled [ServiceClientSSL] enabled [ServiceProxyTunnel] RAW [ServiceClientSSLcert] WASD_ROOT:[LOCAL]HTTPD.PEM # KLAATU WASD_CONFIG_MAP [[*:10023]] # if the client is on the local subnet if (remote-addr:192.168.0.0/24 && request-method:connect) pass *:0 https://gort.domain:10443 timeout=none,none,none endif pass "403"

Destination of tunnel: # GORT WASD_CONFIG_SERVICE [[https://*:10443]] [ServiceProxy] enabled [ServiceProxyTunnel] CONNECT [ServiceProxyAuth] PROXY # GORT WASD_CONFIG_MAP [[*:10443]] # we'll be relying on X509 authentication if (request-method:connect) pass *:0 raw://gort.domain:23 timeout=none,none,none endif pass "403" # GORT WASD_CONFIG_AUTH [[*:10443]] [X509] * r+w,param="[VF:OPTIONAL]",~4EAB3CBC735F8C7977EBB41D45737E37

This works by configuring the destination service to insist on proxy authorization. The authorization realm is X509 which causes the destination to demand a certificate from the source ((hd_ssl_x509_auth)). The fingerprint of this certificate is checked against the authorization rule before the connection is a allowed to procede. (Shared SSH Tunnel\hd_proxy_tunneling_ssh)

The objective of this (raw) tunnel variant (see (hd_proxy_tunneling_raw)) is to allow tunneling of Secure Shell (SSH) via a client site proxy server CONNECT which is usually confined to port 443. Of course most Web servers are configured to provide SSL HTTP on port 443. Sharing of HTTP and SSH on the same port is a little problematic and involves some protocol detection. The following explanation of how it is implemented is so that the reader can understand the requirement for the (timeout quirk).

On configured services; WASD (peeks) at the incoming TCP byte stream to see if it's SSH protocol. If it is, the socket is associated with a proxy raw tunneling service and proxy tunneling initiated to a mapped SSH server. However (just to make it interesting) some SSH clients do not initiate their own exchange until after the SSH server, and so (peeking) only works for a subset of clients. Of course this is a Catch-22 of sorts! To provide for these clients; if an input timeout should occur (an SSH client waiting) WASD sets up the tunnel anyway and begins the proxy. The proxied SSH server should then initiate the protocol and the client respond. The directive [ServiceShareSSH] configured to be non-zero both enables this facility for a service and sets the input timeout period (which perhaps should be shorter than the default 30 seconds because such clients will wait that long for any SSH server response).

This approach seems to work well-enough in practice, although users need to be aware that some clients will pause (for the duration of the timeout period - the (timeout quirk)) during initial connection setup. # WASD_CONFIG_SERVICE [[https://*:443] [ServiceShareSSH] 10 [[http://*:10022]] [ServiceProxy] enabled [ServiceProxyTunnel] raw # WASD_CONFIG_MAP [[*:443] if (request-method:ssh) pass * raw://ssh.server.host:22 \ service=the.proxy.host:10022 \ timeout=none,none,none endif [[*:10022]] pass "403"

This example shows an SSL service, the desired SSH service (which can be local or remote) and the internal proxy service that will provide the connection. (Complex Private Tunneling\hd_proxy_tunneling_complex)

When creating (raw) tunnels between WASD servers, and possibly in other circumstances, it is often useful to be able to signal (tunnel purpose) to the remote end. In this way a single destination port can support multiple tunneling purposes simply through mapping rules. An originating end can (inject) an HTTP request line, or full request, into the established tunnel connection, which can then be processed by the usual WASD request mapping, and from that alternate services provided based on the intent signalled by the originating end.

This somewhat complex but instructive example illustrates the potential utility and versatility of WASD tunneling. It involves an originating WASD server, a destination (service providing) WASD server, and just to make it interesting an intermediate chained HTTP proxy server (not WASD). The idea is to provide access to various application services not necessarily supported by intermediate HTTP proxies and/or gateways. Four services will be supported by the example; SSH, NNTP IMAP and SMTP. (There is a leading (^H) two spaces in on the next line) () inside firewall outside +------------+ +-------------+ +------------+ <-raw->| WASD proxy |<-ENCRYPTED->| other proxy |<-ENCRYPTED->| WASD proxy |<-raw-> +------------+ +-------------+ +------------+ wasd.internal.net proxy.internal.net wasd.external.net proxy.external.net SSH---8022--+ : : +----22---SSH SMTP---8025--|________________________:....:_________________________|----25---SMTP NNTP---8119--| :....: |---119---NNTP IMAP---8143--+ : : +---143---IMAP (Internal Services\hd_proxy_complex_int_services)

These are the services assigned on the WASD server on the inside of the proxy/gateway. Note that there is one per application to be tunneled. For simplicity each service port number has been selected to parallel the well-known application port number. Note that (proxy) is enabled on each (allowing them to initiate outgoing connections) and each has (SSL) enabled (further allowing them to initiate encrypted connections). # client SSH [[http://*:8022]] [ServiceProxy] enabled [ServiceProxyTunnel] RAW [ServiceClientSSL] enabled # client SMTP [[http://*:8025]] [ServiceProxy] enabled [ServiceProxyTunnel] RAW [ServiceClientSSL] enabled # client IMAP [[http://*:8143]] [ServiceProxy] enabled [ServiceProxyTunnel] RAW [ServiceClientSSL] enabled # client NNTP [[http://*:8119]] [ServiceProxy] enabled [ServiceProxyTunnel] RAW [ServiceClientSSL] enabled

Each client application (i.e. IMAP, SSH) must be configured to connect to its corresponding service port (e.g. IMAP to 8143, SMTP to 8025). (Internal Mapping\hd_proxy_complex_int_mapping)

These mappings are made on the WASD server on the inside of the proxy/gateway. The rules essentially initiate an outgoing encrypted (SSL) connection to the host (wasd.external.net) supporting the external WASD proxy server. Each is also configured not to connect directly but to request the chained proxy server (proxy.internal.net) to establish the connection on their behalf. !##### SSH ##### [[*:8022]] pass * https://wasd.external.net:443 notimeout \ proxy=tunnel=request="CONNECT wasd-ssh" \ proxy=chain=proxy.internal.net:8080 !##### SMTP ##### [[*:8025]] pass * https://wasd.external.net:443 \ proxy=tunnel=request="CONNECT external-smtp" \ proxy=chain=proxy.internal.net:8080 !##### NNTP ##### [[*:8119]] pass * https://wasd.external.net:443 \ proxy=tunnel=request="CONNECT external-nntp" \ proxy=chain=proxy.internal.net:8080 !##### IMAP ##### [[*:8143]] pass * https://wasd.external.net:443 \ proxy=tunnel=request="CONNECT external-imap" \ proxy=chain=proxy.internal.net:8080

If the up-stream proxy server successfully connects to (wasd.external.net) port 443 the proxy server allows the byte-stream to be asynchonously and bidirectionally exchanged with the internal WASD server outgoing connection. This internal WASD server has initiated an SSL connection and the external server port 443 expects SSL so they can now both negotiate an SSL-encrypted channel essentially directly with each other. (External Services\hd_proxy_complex_ext_services)

The external WASD service configuration is very simple, a single SSL port. # general SSL service [[https://wasd.external.net:443]] # outgoing proxy/tunnel service [[http://wasd.external.net:1234]] [ServiceProxy] enabled [ServiceProxyTunnel] raw [ServiceClientSSL] ENABLED

Connections to the 443 port are expected to undertake an SSL negotiation to establish an encrypted channel. This includes incoming tunnel connections. The service on port 1234 is required to support the connections outgoing from the external WASD server to the application server ports. (External Mapping\hd_proxy_complex_ext_mapping)

These mappings are all applied to requests at port 443 on the external WASD server (wasd.external.net). Each rule checks three request characterstics. First, the request method, (CONNECT). Second, the request URI, varies according to the request. These are the request data injected by the internal WASD server (wasd.internal.net) using the (set=proxy=tunnel=request=) mapping rule on the outgoing connection. Third, the originating host ((proxy.external.net)) address adds an extra filter on from where this facility may be used. The respective (pass) of the matching rule then initiates an outgoing connection to the respective application server's well-known port. A timeout is applied to limit connection times. !# SSH tunneling [[*:443]] if (request-method:CONNECT && \ request-uri:"wasd-ssh" && \ remote-addr:205.3.*) \ pass * raw://wasd.external.net:22 service=*:1234 timeout=noprogress=00:00:50 !# SMTP tunneling [[*:443]] if (request-method:CONNECT && \ request-uri:"external-smtp" && \ remote-addr:205.3.*) \ pass * raw://smtp.isp.net:25 service=*:1234 timeout=noprogress=00:00:50 !# NNTP tunneling [[*:443]] if (request-method:CONNECT && \ request-uri:"external-nntp" && \ remote-addr:205.3.*) \ pass * raw://news.isp.net:119 service=*:1234 timeout=noprogress=00:00:* !# IMAP tunneling [[*:443]] if (request-method:CONNECT && \ request-uri:"external-imap" && \ remote-addr:205.3.*) \ pass * raw://imap.isp.net:143 service=*:1234 timeout=noprogress=00:00:50 !# disable general 1234 service usage [[*:1234]] pass * 403 "Internal use only!" (Example In Action\hd_proxy_complex_ext_action)

Now let's look at an actual example usage. Consider the internal user's IMAP application, say Thunderbird, is configured to use an IMAP server at host (wasd.internal.net) port 8143. The internal user activates Thunderbird which then intiates an TCP/IP connection to the configured IMAP server expecting to commence the IMAP application protocol.

This connection arrives at (wasd.internal.net) port 8143 which has a WASD (raw) tunnel service listening. The connection is accepted and request processing commences. Mapping rules applied to port 8143 initiate an SSL connection to host (wasd.external.net) which is not directly accessable because of the firewall and must be connected to using the HTTP proxy server (proxy.internal.net) as an intermediary. This is specified in the same mapping rule. The mapping rule also injects an HTTP request header providing request characteristics that can be identified and acted upon by the external server.

The internal WASD server initiates a connection to the proxy server (proxy.internal.net) acting as part of the firewall. As it is endeavouring to initiate an SSL connection with the external (wasd.external.net) host this proxy connection uses a CONNECT request specifying (wasd.external.net) port 443. The proxy server establishes a connection with the host (wasd.external.net) at port 443. Once the connection is established it becomes an asynchronous, bidirectional channel between (wasd.internal.net) and (wasd.external.net) with the proxy server as a conduit.

The service connection just established is expecting an SSL negotiation in an attempt to establish an encrypted channel. When this negotiation concludes successfully the communications between (wasd.internal.net) and (wasd.external.net) become opaque to all external listeners including (proxy.internal.net).

The encrypted connection now established, the request begins to be processed by the WASD server at (wasd.external.net). A number of mapping rules apply to port 443. Each rule compares the injected request method and URI until, in this case, the (external-imap) rule matches. This rule specifies that a raw connection be established with the host (imap.isp.net) at port 143 using the proxy-capable port 1234 service. A timeout limits the duration this connection can be held unused.

The IMAP application server at (imap.isp.external) port 143 accepts the connection at begins to communicate using the IMAP protocol.

There is now a raw (8 bit, asynchronous, bidirectional) connection from the Thunderbird client to (wasd.internal.net), (encrypted) through to (proxy.internal.net), (encrypted) through to (wasd.external.net), and raw to the IMAP server at (imap.isp.net). This raw connection will be used for communication between Thunderbird and the IMAP server using the IMAP application protocol. (Tunnelling Source\hd_proxy_tunneling_source)

When a tunnel is established into a system the source of that connection (IP host-name/address and port) becomes obscured. By setting the path to the destination port (proxy=forwarded=for) (host name) or (proxy=forwarded=address) (IP address) the external client can be obtained using data contained in the logical name WASD_TUNNEL.

Consider tunneling external port 22345 to internal port 22 - Secure Shell. # WASD_CONFIG_SERVICE [[http://*:22345]] [ServiceProxy] enabled [ServiceProxyTunnel] RAW # WASD_CONFIG_MAP [[*:22345]] pass * raw://localhost:22 notimeout

To Secure Shell the source host and port would be (localhost) and (some random port). It can be useful for the login procedure or other service to have the actual client host name (or IP address). Adding the path setting. # WASD_CONFIG_MAP [[*:22345]] pass * raw://localhost:22 notimeout proxy=forwarded=address will result in connection data becoming available in the multivalued logical name WASD_TUNNEL. Index 0 contains internal data, and then the rest (1..127) contain one tunneled connection's details each, in the format (())=(())=(()) For example localhost:46851=www.external.net:22345=mydotcom.org:49201

Obtaining the SSH source port, say from TT_ACCPORNAM data, the original client host and port can be searched for with some trivial DCL code. Adapt to suit local requirements. $ if P1 .eqs. "" then P1 = f$element(1,":",f$getdvi("TT:","TT_ACCPORNAM")) $ value = "" $ local = "" $ service = "" $ client = "" $ index = 1 $ index_loop: $ value = f$trnlnm("WASD_TUNNEL","WASD_TABLE",index) $ if value .eqs. "" then goto end_index_loop $ local = f$element(0,"=",value) $ addr = f$element(0,":",local) $ port = f$element(1,":",local) $ if port .eqs. P1 $ then $ service = f$element(1,"=",value) $ client = f$element(2,"=",value) $ goto end_index_loop $ endif $ index = index + 1 $ goto index_loop $ end_index_loop: $ if f$trnlnm("TT_CLIENT","LNM$PROCESS") .nes. "" - then deassign /process TT_CLIENT $ if client .nes. "" then define /process TT_CLIENT "''client'"

The tunnel data remains current for at least one minute and may become unavailable at any time after that. The source data only reflects the client that connects to that system's services and so cannot be used across multiple, back-to-back tunnels. (Browser Proxy Configuration\hd_proxy_browser_config)

The browser needs to be configured to access URLs via the proxy server. This is done using two basic approaches, manual and automatic. (Manual\hd_proxy_browser_manual)

Most browsers allow the configuration for access via a proxy server. This commonly consists of an entry for each of the common Web protocol schemes ((http:), (ftp:), (gopher:), etc.). Supply the configured WASD proxy service host name and port for the HTTP scheme. This is currently the only one available. This would be similar to the following example: http: www.example.com 8080

To exclude local hosts, and other servers that do not require proxy access, there is usually a field that allows a list of hosts and/or domain names for which the browser should not use proxy access. This might be something like: www.example.com,example.com,example.com (Automatic\hd_proxy_browser_automatic)

At least Netscape Navigator/Communicator and Microsoft Internet Explorer (4.(n) and following) provide the facility to download a small JavaScript function for establishing proxy policy. Information on this function and its deployment may be found at (HTML=http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/proxy-live.html) (HTML/OFF)

http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/proxy-live.html (HTML/ON)

The following is a very simple proxy configuration JavaScript function. This specifies that all URL host names that aren't full qualified, or that are in the (example.com) domain will be connected to directly, with all other being accessed via the specified proxy server. function FindProxyForURL(url,host) { if (isPlainHostName(host) || dnsDomainIs(host, ".example.com")) return "DIRECT"; else return "PROXY www.example.com:8080; DIRECT"; }

This JavaScript is contained in a file with a specific, associated MIME file type, (application/x-ns-proxy-autoconfig). For WASD it is recommended the file be placed in WASD_ROOT:[LOCAL] and have a file extension of .PAC (which follows Netscape naming convention).

The following WASD_CONFIG_GLOBAL directive would map the file extension to the required MIME type: [AddType] .PAC application/x-ns-proxy-autoconfig - proxy autoconfig

This file is commonly made the default document available from the proxy service. The following example shows the HTTP$MAP rules required to do this: [www.example.com:8080] pass http://* http://* pass / /wasd_root/local/proxy.pac pass *

All that remains is to provide the browser with the location from which load this (automatic proxy configuration) file. In the case of the above set-up this would be: http://www.example.com:8080/

A template for a proxy auto-configuration file may be found at (HTML= WASD_ROOT:[EXAMPLE]PROXY_AUTOCONFIG.TXT ) (HTML/OFF) WASD_ROOT:[EXAMPLE]PROXY_AUTOCONFIG.TXT. (HTML/ON) (--------------------------------------------------------------------)