Telenet session response delay

[affin]

Dear All,


we have an 11.0 box that presents the following issue:

trying to acces it by telnet, the session takes some seconds (at least 10-15) prior to get the login and password prompt?
I checked out dmesg, syslog, rc.log but all seems to be ok.The lan connection is autoneg.an now is set to 100Mbit FULL DUPLEX.
Anyone has an idea?


Many Thanks!
Alessandro.

[Yogeeraj_1]

hi,

may be associated with dns settings.

check your /etc/nsswitch.conf.

should have line for "hosts" as:
hosts: files [NOTFOUND=continue] dns

hope this helps!

regards
yogeeraj

[Pat Lieberg]

If I remember correctly, telnet does a reverse lookup on the host that's connecting to it. You might check the name resolution coonfiguration on your 11.0 system. It's possible the first resolution mechanism is failing and timing out then moving on to the secondary.

This could be the delay you are seeing.

[affin]

here my nsswitch.conf

hosts: files [NOTFOUND=continue UNAVAIL=continue] dns [NOTFOUND=return UNAVAIL=continue TRYAGAIN=continue] nis [NOTFOUND=return UNAVAIL=continue TRYAGAIN=return]



...the NDS settings sseems to be ok...

[affin]

The DNS and hostname resolution seems to be ok.The same problem occurs if for example I try to execute a ping.

A.

[Yogeeraj_1]

hi again.

is it on the same lan?

can you try a simple test by putting the IP address of the client in the hosts file (/etc/hosts)?

regards
yogeeraj

[Pat Lieberg]

You can also check /etc/resolv.conf and check to see if the primary dns server you have listed in there is down?

When doing your test pings, are you ping-ing a hostname or an ip address?

[Bill Hassell]

Probably the most frequently asked question about telnet login connections. It will take 15-20 seconds for each of the DNS servers listed in /etc/resolv.conf when those severs cannot do a reverse lookup (IP = what host?). This is an authentication step to see that any old IP address cannot (easily) get into the login program.

So if all 3 of your resolv.conf servers cannot find this IP address, it will take about 90 seconds before you see a prompt. To fix this, change your resolver order in nsswitch.conf from the typical dns->nis->files to files -> dns. Then put in dummy names in /etc/hosts for the incoming IP addresses that take a long time. nslookup will also show you the problem. In fact, nslookup will check that your DNS server knows (or doesn't) his own name.

[Bejoy C Alias]

If u have tcpdump installed in the server , try observing the communication between the client and the server using 'tcpdump -pni lan0 host ' and check where it is taking time .

[zhi wang_1]

I had similar experiences before. It was caused by the "decommision" of the primary DNS server but we were not notified (the network group manages the DNS). Please check with your DNS management group and update your resolve.conf file. First try to ping and nslookup your primary DNS server and see if it is up and running. Promote the 2ndary DNS to the first line and try again.

[affin]

The problem was related to NIS configuration.
The box had a NIS client configured but no NIS Server was present in our farm. Disabling it and reviewing nsswitch.conf solved the issue.


Thanks all.

A.