SERVER parameter*   ==  SERVER=protocol[://host[:portNum]][:-:MountOptions]
           portNum  ==  [+|-]number
                    --  default: SERVER=delegate

SERVER=protocol specifies the protocol to be used for communication with clients, which will be the default protocol with servers.

Example: a SERVER parameter for unbound Telnet-DeleGate

SERVER=telnet
If SERVER="delegate" is given, the DeleGate will become a generalist (or MASTER-DeleGate), which acts as an upstream DeleGate of other DeleGates. Note that a generalist can remit arbitrary protocols by default, so that it can be dangerous without enough consideration on access control (see REMITTABLE). A generalist automatically detects multiple protocol, including HTTP, proxy-Whois, as well as DeleGate original protocol.

If no destination server (host) is specified, it is to be be given by client somehow at run-time, on application level in protocol dependent way.

Several protocols including "http" and "socks" have inherent and automatic way to do proxying. Some protocols, like "ftp" and "pop", with a subprotocol to login to server are naturally extended so that information about destination server is encoded as user@host for user name as login information. Some protocols, including "whois" and "gopher", in which the first message is sent from client side, typically as a query message, the message is extended (without changing the specification) to include information about destination server. Some of other protocols like "telnet" have interaction with user on a client program thus can be extended with login dialogue for proxying.

The protocol with server is implicitly expected to be the same with the protocol with the client. Some protocols like HTTP have their inherent way to specify the protocol with the destination server. Otherwise it must be explicitly given with MOUNT parameter, like MOUNT="/news/* nntp://server/*" for example.

SERVER=protocol://host:portNum specifies the URL of destination server. The ":portNum" part is omittable as usual in URL if the number is that of standard port number of the protocol. A list of protocols and standard port numbers recognized by the DeleGate is available at: "http://delegate/-/builtin/mssgs/config.dhtml".

Port mapping: If a portNum is prefixed with "-" or "+", it means mapping the port number of the entrance port adding the specified offset, or using the port number as is by "-" with empty portNum.

Example: forwarding multiple ports to an another host

-P21,23,25,80 SERVER=tcprelay://host:-/

A special hostname "odst.-" can be used to refer the original destination host when the incoming data is forwarded by NAT.

Example: forwarding NAT to the original destination via a SOCKS proxy

-P9999 SERVER=tcprelay://odst.-:- SOCKS=sockshost

Note that a DeleGate bound to a specific server is not disabled to work as a proxy for arbitrary servers. Proxying ability must be restricted if necessary, using PERMIT, REACHABLE and RELAY parameters.

If a SERVER parameter is with ":-:MountOptions", the SERVER parameter will be dynamically selected if the condition specified in the MountOptions is evaluated to be true. As a special case, ":-:via=HostList" can be abbreviated as ":-:HostList".

Example: selecting an appropriate NNTP server for a client

SERVER="nntp://newsserver1:-:from={*.dom1}"
SERVER="nntp://newsserver2:-:from={*.dom2}"

Example: {NNTP,SMTP,POP}-DeleGate as a single server

-P119,110,25
SERVER="nntp://nntpserver:-:{*:119}"
SERVER="smtp://smtpserver:-:{*:25}"
SERVER="pop://popserver:-:{*:110}"