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Cannot connect with telnet

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pjw001

Technical User
Aug 12, 2002
297
GB
Our Unix and Windows systems have been relocated and I am now on a different Windows domain.

I can connect to one of our Unix servers but not to the other except by going via the one I can connect to.

When I try to connect from my PC with telnet it sits there for while and then just exits. No error message, just the command prompt back again.

The system is SCO UnixWare 7.1.1.

If I ping the machine I get a reply.

Does anyone have any ideas please?
 
Not familiar with Unixware but had same sort of problem in Openserver once. Do you have a tcp-wrapper activ? You might want to look for a /etc/hosts.allow and /etc/hosts.deny


Greetz, Wim. Please remember, The Netherlands is in a different timezone.
 
Thanks for the reply, but neither of those files exist.
 
Have you checked there is a route to your new location network.

Compare your route tables, netstat -r also is there a firewall in between?
 
the windows domain change means nothing w.r.t. telnet.

your ip address and subnet is what matters.
since you can ping your routing should be ok.

connect to the problem machine by bouncing thru the other working machine and see if you can ping by NAME to your PC.

telnet servers can be finicky if they can't do a reverse lookup on the client machine.
 
I had to double check that this wasn't me posting (my initials happen to be pjw also :) )

Some thoughts:
1) SCO needs RIP enabled before it will allow a connection. Maybe one machine's firewall has it enabled and one dosn't?
2) If the machines are on an internal network, your IP range and netmask matter unless you have access to a gateway router.
3) If the unreachable machine is also on the internet, try using the external address to get at it from the internet side
4) You can automate the 'sideways' hop from one UW7 machine to the other by adding some lines to your home .profile, something like:

echo "\n Jump to the Xyz machine? (Y/N) \c"

read jump

if [ "$jump" = "Y" -o "$jump" = "y" ]
then
telnet <machine name or address>
exit #Skip this if it's OK to drop back to 1st box.
fi

- If you enter Y or y it will telnet to the other machine, anything else and it will drop through.

You can do something similar with many Telnet/SSH clients that allow you to script logins by responding to specific strings during the login.

In that case wait for the $ prompt of the 1st box and make the next action the telnet to the 2nd one.



----------------------------------------------------
Pat Welch, UBB Computer Services, a WCS Affiliate
SCO Authorized Partner
Microlite BackupEdge Certified Reseller
Unix/Linux/Windows/Hardware Sales/Support
(209) 745-1401 Cell: (209) 251-9120
E-mail: patubb@inreach.com
 
This is in reply to stanhubble - sorry for the delay, I thought I had replied but must have pressed the wrong button.

I logged into Unix machine 'abc' from Windows XP machine 'xyz' and tried to ping 'xyz'.

This is what happened.

abc:/> ping xyz.domain1.net
mno.domain1.net is alive

So what is machine 'mno' and does this have anything to do with my problem?

(I've changed the machine and domain names to protect the guilty!)
 
Could be a dup IP number between you and xyz.

Or a polluted local DNS needs refreshing.

What name does a ping by IP number return?


----------------------------------------------------------------
Pat Welch, UBB Computer Services, a WCS Affiliate
SCO Authorized Partner
Microlite BackupEdge Certified Reseller
Unix/Linux/Windows/Hardware Sales/Support
(209) 745-1401 Cell: (209) 251-9120
E-mail: patubb@inreach.com
 
If I ping 'mno' (from the Unix system) I get

ICMP Net redirect from gateway 172.21.1.2
to 172.21.2.1 for cfl373.domain1.net (192.168.56.123)
UX:ping: INFO: no answer from cfl350.domain1.net

If I ping my XP machine by IP address it says it is alive.
 
More info - thats good. Is your PC on one of the 172.21.x. subnets or the 192.168.56 one?

Either way, you need to look at the routing rules in place on the gateways, and/or the local DNS server machine maps need to be refreshed.

If you don't have admin privleges on those, then you'll have to turn the problem over to the admins.

Finally, can you telnet by IP number to the other Unix server? If it returns "No route", then the gateway has to be setup.

If it gets through, then either always use the IP number or add the name/IP number to your XP's hosts file.

----------------------------------------------------------------
Pat Welch, UBB Computer Services, a WCS Affiliate
SCO Authorized Partner
Microlite BackupEdge Certified Reseller
Unix/Linux/Windows/Hardware Sales/Support
(209) 745-1401 Cell: (209) 251-9120
E-mail: patubb@inreach.com
 
Thank you for your help.

My subnet mask (as shown by ipconfig) is '255.255.255.0'.

If I try to telnet by IP number it simply sits there for a while and then returns to the dos prompt without any message.

I also tried with the -f option but the log file was empty.

I don't have admin priveliges to anything other than my own pc and the Unix box, which gives me an idea.

I've just put an entry for my pc in the hosts file on the Unix machine and Hey Presto, it works.

Thanks very much to everyone who has helped me in this.
 
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