2004-11-01 03:33:54

by ych43

[permalink] [raw]
Subject: TCP port numbers

Hi,
I got one question about unix socket functions. I have two machines (called A
and B). I use A to telnet B, get the root password of B. Is there any unix
socket function I can use to get the port number of A on B. Obviously, the
port number of B is 23. I want to use a socket function implemented on B to
get the port number of A because a TCP connection is established between them.
I greatly appreciate it if you help me. Thank you in advance.
Xue


2004-11-01 10:39:11

by Jan Engelhardt

[permalink] [raw]
Subject: Re: TCP port numbers


>Hi,
> I got one question about unix socket functions. I have two machines (called A
>and B). I use A to telnet B, get the root password of B. Is there any unix
>socket function I can use to get the port number of A on B. Obviously, the

The 'struct sockaddr_in' you're filling in on B's site with the call with
accept() also fills in the port number.

>port number of B is 23. I want to use a socket function implemented on B to
>get the port number of A because a TCP connection is established between them.
> I greatly appreciate it if you help me. Thank you in advance.
> Xue


Jan Engelhardt
--
Gesellschaft für Wissenschaftliche Datenverarbeitung
Am Fassberg, 37077 Göttingen, http://www.gwdg.de

2004-11-01 12:46:38

by Neil Horman

[permalink] [raw]
Subject: Re: TCP port numbers

ych43 wrote:
> Hi,
> I got one question about unix socket functions. I have two machines (called A
> and B). I use A to telnet B, get the root password of B. Is there any unix
> socket function I can use to get the port number of A on B. Obviously, the
> port number of B is 23. I want to use a socket function implemented on B to
> get the port number of A because a TCP connection is established between them.
> I greatly appreciate it if you help me. Thank you in advance.
> Xue
>
I think getpeername is the library call you are looking for
HTH
Neil
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/***************************************************
*Neil Horman
*Software Engineer
*Red Hat, Inc.
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