What are these ports for?
Rohan Beckles
However, the machine it's running on is behind a NAT'd router, so nobody
can access the port from the outside. What exactly is it used for?
Another question: does anyone know what port 641 is used for?
Thanks in advance,
Rohan Beckles
Chief Systems Architect
Metanix Limited
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ynotssor
> I've noticed that Yahoo!'s Instant Messenger application uses port 5101.
> However, the machine it's running on is behind a NAT'd router, so nobody
> can access the port from the outside. What exactly is it used for?
>
> Another question: does anyone know what port 641 is used for?
From http://www.iana.org/assignments/port-numbers :
repcmd 641/tcp repcmd
repcmd 641/udp repcmd
talarian-tcp 5101/tcp Talarian_TCP
talarian-udp 5101/udp Talarian_UDP
Of course, if you have things active on these ports they may be entirely
different programs. You should be intimately familiar with what's happening
on every port.
lsof -i :641,5101
will tell you about those 2 ports, then lsof -p PID to get more info if needed.
BTW, a NAT router doesn't provide you with any firewall protection unless it is
a firewall device as well. You seem somewhat trusting about it, so allow
me to suggest an nmap port scan of your access point from both inside and
outside your network.
You may be surprised at what you see.
tony
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$uRoot
> I've noticed that Yahoo!'s Instant Messenger application uses port 5101.
> However, the machine it's running on is behind a NAT'd router, so nobody
> can access the port from the outside. What exactly is it used for?
>
> Another question: does anyone know what port 641 is used for?
>
> Thanks in advance,
>
> Rohan Beckles
> Chief Systems Architect
> Metanix Limited
>
No offense, but I should hope that a "Chief Systems Architech" knows how
to use google.
http://www.iana.org/assignments/port-numbers
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=tcp+port+641&btnG=Google+Search
http://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=tcp+port+5101&btnG=Google+Search
Good luck.
--
William Carty
http://www.thinktankdecoy.com
If replying by mail, see the reply-to header
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Rohan Beckles
There seems to be a certain amount of confusion over my introductory
message. My point is this: my Windows workstation (on which Yahoo! IM is
running) is sitting on a LAN with private, non-routable addresses - one
Windows 2000 machine, one RedHat Linux 8.0 machine. "In front" of the LAN
is the router, which is a DSL modem and router combined, and has both NAT
and port forwarding. None of my machines are exposed directly to the
Internet.
I haven't opened the port on the router to allow incoming connections to
port 5101 on any machine on my private LAN (like I have to with my web
server and QTella P2P client (ports 80 and 6346 respectively).
So, if Yahoo! IM needs port 5101, how does it manage to function, if there
are no incoming connections to the machine with that port open?
Hope this clears up the confusion.
Best,
Rohan Beckles
Chief Systems Architect (Java software only!), Metanix Limited
rohan....@metanix.com
ynotssor
[...]
> I haven't opened the port on the router to allow incoming connections to
> port 5101 on any machine on my private LAN (like I have to with my web
> server and QTella P2P client (ports 80 and 6346 respectively).
>
> So, if Yahoo! IM needs port 5101, how does it manage to function, if there
> are no incoming connections to the machine with that port open?
The client PC establishes the initial connection with the IM server on port
5101, stating to the server that it is available for communication with other IM
clients.
Because the client PC established the initial outbound connection, the router
allows inbound responses/connections from the IM server to the PC client that
established the initial connection, but no others (unless they too have established
an initial connection with the IM server).
Rohan Beckles
a client side socket would only be in the high range, 30000 and upwards.
Continuing along the same line of thought, have you ever gotten IM clients
to transfer files to each other from behind a NAT router?
Thanks for any advice,
Rohan Beckles
Chief Systems Architect, Metanix Limited
ynotssor
>
> Thanks for that, now I understand what is going on - I wrongly assumed that
> a client side socket would only be in the high range, 30000 and upwards.
>
> Continuing along the same line of thought, have you ever gotten IM clients
> to transfer files to each other from behind a NAT router?
I don't use such clients.
Your answer may be within http://help.yahoo.com/help/us/mesg/unix/index.html