TCP port numbers

TCP port numbers

[ych43]

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

Re: TCP port numbers

[Jan Engelhardt]

>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, www.gwdg.de

Re: TCP port numbers

[Neil Horman]

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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