how to give Telnet access

Hello,

I have recently taken over administration of a Sco Unixware server (Version 7.1.4), but have no previous experience with Unix.

I now have the following problem: Most computers on the network are unable to Telnet to the Unix server but some PCs with privileged users can, which is fine. I now need to allow Telnet access to the server for another PC but I can't find where this has been configured.

I have checked the /etc/inet/hosts.allow and hosts.deny files but these files appear to have default values that are all commented out. I have checked for access-lists on the Layer 3 switch that connects the host to the server but there are no access lists configured. All hosts on the network can ping the server and access the server through SSH so there are no communication issues between host and server. When the host that I am trying to grant access tries to Telnet to the server from a command prompt in Windows the CMD window is just blank with a flashing cursor which then times out and returns to the usual command prompt.

Does anybody know where access rules for Telnet might be configured on this Sco server?

Many thanks,
Nick

Isn't ssh available ?

Well, telnet is not secure, and open ssh2 is free, secure, can compress, can support batch, so why?

Do their logins work at the console?

Is there any firewall on this host or between?

What happens when they telnet?

See if this helps: Understanding, debugging, and tuning UnixWare 7 telnet connections.

Hi, thanks for your replies.

I totally agree about SSH but in this case a program has been written by somebody who has left the company that accesses the server using Telnet and then runs some macros. This program only needs to run on a couple of admin PCs and it would be good if I can just resolve this Telnet issue until such time as we can achieve the same goal using SSH. All other PCs on the network use an SSH client to access the application running on the Sco server.

Also I would like to understand the problem. If I just go to my boss and say "Well, we should be using SSH" then, although that is true, I'm more or less saying that I don't understand the issue and can't solve it, and it should be so simple.

When I Telnet to the server from my Windows PC I get a login prompt and can successfully log in, no problems. When my colleague tries the same thing she does not even get a login prompt, just a blank CMD window with a flashing cursor which then times out. If I change her PC's IP address to the IP address on my PC she can Telnet to the server with no problems, so it is an IP address restriction.

My colleague can ping the server and access it using SSH so there are no communication issues. As to firewalls that is what I don't know about as I'm very new to UNIX. There are no firewall rules configured between the host and the server that might be blocking the connection but as to what is running on the server itself I don't know. Before I joined this forum I read about TCP wrappers but these don't seem to be configured so I'm stumped.

Cheers,
Nick

The telnet daemon (telnetd) is invoked by the internet services daemon (inetd), which consults /etc/inet/hosts.allow and /etc/inet/hosts.deny for access rights. A host is granted access for a server/service if

  1. it is explicitly allowed in hosts.allow
  2. it is not explicitly denied in hosts.deny

Check those two files for any configuration problems.

In the long run, try to find out how you or someone else in your company can change that program to use SSH instead of telnet.

I would look at the firewall rules that protect your server. It may just be that port 23 is only allowed through for certain PCs. The timeout would support this.

Does a ping or tracert from a DOS window help?

Robin
Liverpool/Blackburn
UK

UnixWare 7.1.4 Maintenance Pack 3 included IPfilter, so you might have that installed. Search for ipf on this page (see especialy the part with links to 2 other pages regarding ipf): What problems are fixed by UnixWare 7.1.4 Maintenance Pack 3 and how can I obtain it?