Telnet login prompt taking too long

[Joe Profaizer]

On two of my three systems, it has been noticed that it takes about 20-25 seconds to get a login prompt via telnet. Are there any obvious places to start looking besides the network. Our networking staff has told me the network is OK. I currently have one 1000Base-SX card enabled and one fast ethernet card that is disabled. Thie IP addresses synch. up with the correct cards also.

Thanks,

..Joe

[James R. Ferguson]

Hi Joe:

If you have DNS enabled, then you probably have delays due to "reverse name lookup".

Making sure that your device's name is represented in the DNS tables of the DNS server will eliminate the (timeout) delay.

Reverse lookup is the process by which a server receiving a request for service from a remote machine ascertains whether the identity claimed by the machine is in fact its true one. The process goes like this:

1. The request arrives in a packet with an IP address indicating the point of origin.
2. The server queries name service on the net to find out what host name is associated with that IP address.
3. The server then queries name service to find out what IP address is associated with that host-name.
4. If this last request fails to find an IP address, or finds one that doesn't match the original, the request for service is rejected.

For an good description of reverse name lookup, see:

http://www.helpdesk.umd.edu/comm/ethernet/revlook.shtml

...JRF...

[Joe Profaizer]

DNS is disabled. Also, we're trying telnet w/ the IP address and still getting the delayed logins.

Thanks,

..Joe

[Joe Profaizer]

Excuse me, the DNS server is an Windows 2000 Server. Sorry. And all client PCs have DHCP enabled.

[Brian Hackley]

Joe,
Going back to James' suggestion, either edit /etc/nsswitch.conf "hosts" entry to read:
hosts: files
and test, OR mv /etc/resolv.conf /etc/resolv.conf.save
to temporarily disable DNS.
Also see if using NIS Domain name is set since NIS Server can do DNS lookups for you and cause the same delay. Just running domainname . You either get your NIS domainname or
"NIS domain name not set". If you get NIS domainname then temporarily disable it:
domainname ""
Now test.
Restore /etc/resolv.conf and your NIS domain if needed when testing completes.
Lastly if the above suggestions fail, perhaps /etc/wtmp utmp btmp might be having problems? If so you might need to fix the problems in single user mode e.g. cat /dev/null > /etc/wtmp ...
Hope all this helps,
-> Brian

[Pedro Sousa]

Hi Joe!
Check the differences between your 3 systems relating /etc/hosts, /etc/resolv.conf and /etc/nsswitch.conf.

I had a similar problem, and I had to restart rpc and inetd. But I use DNS.
good luck.

[Ravi_8]

hi, joe
i do agree with JRF and Brian. we too have Hp systems with NIS enabled and correct entry made in DNS. In nsswitch.conf file system will look into files first and then in yp(nis), but still we too have this same. by analysis made by us the congestion in the n/w causes this problem

[Pedro Sousa]

Hi again.
So, you are using DNS. Have you made some changes to the above files lately?
My probelm was due to a change in the DNS address and domain. Has I changed the domain, I had to reconfigure the RPC by restarting it. A reboot is the best way to do it. If you can...