topic Re: cant telnet into another subnet in Operating System - HP-UX

cant telnet into another subnet

mkhan_1 — Mon, 05 Feb 2007 16:05:58 GMT

hi guys, for some reason i cannot telnet to another subnet, but can do so to its own.
Example. I can telnet any host on 142.238.210.x but cannot do so on 142.238.64.x The ip address of the host is 142.238.210.236.
I can ping to the gateway, but telnet is not possible.

Re: cant telnet into another subnet

Steven E. Protter — Mon, 05 Feb 2007 17:43:21 GMT

Shalom,

Most likely possible causes.

1) telnet is not secure, some routers now can be configured to block it.
2) No telnet server at the other end. Check the configuration of inetd.conf
3) Firewalls often block telnet

For items 1/3 see the network administrator.

For item 2, fix it admin :-)

SEP

Re: cant telnet into another subnet

Anshumali — Tue, 06 Feb 2007 00:31:34 GMT

I will start like:

1. Is the host on 142.238.210.x pingable?
2. Is that host on 142.238.210.x accepting telnet from any other host on same subnet of 142.238.210.x.
3. If answer to 2 is Yes, its clear that router in between blocking the traffic on port 23(whatever) from subnet 142.238.210.x to 142.238.64.x.
4. If the answer to 2 is No, its certain that issue is with telnet'ed server. You need to check for telnet services and config.

Cheers!!

Re: cant telnet into another subnet

Laurent Menase — Tue, 06 Feb 2007 07:13:08 GMT

1) check your netmask 255.255.128.0 less
(255.255.192.0,255.255.224.0 .......)
2) check you have a route ( default or 142.210.128.0 ( depending of your netmask))
3) check the peer have a route to your 142.38.64.X

Re: cant telnet into another subnet

Georg Tresselt — Tue, 06 Feb 2007 08:12:08 GMT

And don't forget to double-check as well the host you are trying to connect to on the other subnet. If it has its default gateway misconfigured, no answer will get through.

Re: cant telnet into another subnet

Ignacio Javier — Tue, 06 Feb 2007 11:06:19 GMT

Hi:

You could make a linkloop comand to the machine you want to ping, to se if there is a layer2 problem.

If you do not have this level conectÃvity, it could be a layer1 problem

If you have link, check the routing table with netstat -r
You should have a default route so the ip packets go that way when the destination is not known, is not in the same subnet.

Do you have access to the gateway ? Can you ping the destination subnet from that point ?

If not, there it is your problem. If not, maybe the destination hosts you are "pinging", may be do not have the right ( come back ) routes

I hope it helps