Re: Telnetting to diff IP with same port number

Tom Anderson <>
Tue, 27 Apr 2010 19:27:39 +0100
On Tue, 27 Apr 2010, tukker wrote:

        I am new to JAVA world.
        Is it possible to have a telnet service running and lesion on
port let say 233, but the telnetd should be able to service for
multiple IP address.

Yes. This is the default behaviour of a ServerSocket which doesn't have a
specified local address. It's also the behaviour of a ServerSocket created
with an explicit null address, and for that you can rely on the API docs:,%20int,

  The bindAddr argument can be used on a multi-homed host for a
  ServerSocket that will only accept connect requests to one of its
  addresses. If bindAddr is null, it will default accepting connections on
  any/all local addresses.

It's also the behaviour of a ServerSocket bound to the address (at
least on my machine - is this portable?). This is useful to know when you
have an API that absolutely requires a bind address.

                           Lets assume the telnetd is running on a
single windows m/c and we have routes added on to saying any telnet
request with port 233 to IP address or go via

If it's specifically routed via loopback, i think you could even bind to and receive all the connections.


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