url: Gateways in general
5.3 Gateways in General
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The library provides a general gateway layer through which all
networking passes. It can both control access to the network and
provide access through gateways in firewalls. This may make direct
connections in some cases and pass through some sort of gateway in
others.(1) The library’s basic function responsible for making
connections is ‘url-open-stream’.
-- Function: url-open-stream name buffer host service
Open a stream to HOST, possibly via a gateway. The other arguments
are as for ‘open-network-stream’. This will not make a connection
if ‘url-gateway-unplugged’ is non-‘nil’.
-- Variable: url-gateway-local-host-regexp
This is a regular expression that matches local hosts that do not
require the use of a gateway. If ‘nil’, all connections are made
through the gateway.
-- Variable: url-gateway-method
This variable controls which gateway method is used. It may be
useful to bind it temporarily in some applications. It has values
taken from a list of symbols. Possible values are:
‘telnet’
Use this method if you must first telnet and log into a
gateway host, and then run telnet from that host to connect to
outside machines.
‘rlogin’
This method is identical to ‘telnet’, but uses ‘rlogin’ to log
into the remote machine without having to send the username
and password over the wire every time.
‘socks’
Use if the firewall has a SOCKS gateway running on it. The
SOCKS v5 protocol is defined in RFC 1928.
‘native’
This method uses Emacs’s builtin networking directly. This is
the default. It can be used only if there is no firewall
blocking access.
The following variables control the gateway methods.
-- User Option: url-gateway-telnet-host
The gateway host to telnet to. Once logged in there, you then
telnet out to the hosts you want to connect to.
-- User Option: url-gateway-telnet-parameters
This should be a list of parameters to pass to the ‘telnet’
program.
-- User Option: url-gateway-telnet-password-prompt
This is a regular expression that matches the password prompt when
logging in.
-- User Option: url-gateway-telnet-login-prompt
This is a regular expression that matches the username prompt when
logging in.
-- User Option: url-gateway-telnet-user-name
The username to log in with.
-- User Option: url-gateway-telnet-password
The password to send when logging in.
-- User Option: url-gateway-prompt-pattern
This is a regular expression that matches the shell prompt.
-- User Option: url-gateway-rlogin-host
Host to ‘rlogin’ to before telnetting out.
-- User Option: url-gateway-rlogin-parameters
Parameters to pass to ‘rsh’.
-- User Option: url-gateway-rlogin-user-name
User name to use when logging in to the gateway.
-- User Option: url-gateway-prompt-pattern
This is a regular expression that matches the shell prompt.
-- User Option: socks-server
This specifies the default server, it takes the form
‘("Default server" SERVER PORT VERSION)’ where VERSION can be
either 4 or 5.
-- Variable: socks-password
If this is ‘nil’ then you will be asked for the password, otherwise
it will be used as the password for authenticating you to the SOCKS
server.
-- Variable: socks-username
This is the username to use when authenticating yourself to the
SOCKS server. By default this is your login name.
-- Variable: socks-timeout
This controls how long, in seconds, to wait for responses from the
SOCKS server; it is 5 by default.
-- User Option: socks-nslookup-program
This the ‘nslookup’ program. It is ‘"nslookup"’ by default.
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