topic Re: cannot telnet to server in Operating System - HP-UX

cannot telnet to server

tom quach_1 — Wed, 13 Jun 2007 19:02:38 GMT

Dear all,

we have experienced some problem this Morning.
users complaned that they could not connect to the server and even myself i could not connect for about 10 mins.
when i was able to connect, ran glance and it shown me
the history.
--NETWORK BOTTLENECK
--DISK BOTTLENECK

the syslog.log

Jun 13 08:06:10 sunuxap2 inetd[956]: telnet/tcp: accept: Bad file number
Jun 13 08:06:19 sunuxap2 inetd[956]: telnet/tcp: accept: Bad file number
Jun 13 08:06:29 sunuxap2 above message repeats 2 times
Jun 13 08:07:02 sunuxap2 inetd[956]: telnet/tcp: accept: Bad file number
Jun 13 08:09:02 sunuxap2 telnetd[15164]: getpid: peer died: Error 0
Jun 13 08:07:11 sunuxap2 inetd[956]: telnet/tcp: accept: Bad file number

ran lanadmin -g 0
and it came back with
Inbound Errors=0
Outbound Errors=0

the logfile /var/adm/nettl.LOG00
shown some errors but 2 days ago, so this one would not count.

<2004> 1000Base-T in path 0/0/10/0/0
Detected a faulty or disconnected cable.

**********************Gigabit Ethernet LAN/9000 Networking******************@#%
Timestamp : Mon Jun 11 PDT 2007 13:09:35.770698
Process ID : [ICS] Subsystem : IGELAN
User ID ( UID ) : -1 Log Class : ERROR
Device ID : 2 Path ID : 0
Connection ID : 0 Log Instance : 0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

<2004> 1000Base-T in path 0/0/10/0/0
Detected a faulty or disconnected cable.

**********************Gigabit Ethernet LAN/9000 Networking******************@#%
Timestamp : Mon Jun 11 PDT 2007 13:11:23.770696
Process ID : [ICS] Subsystem : IGELAN
User ID ( UID ) : -1 Log Class : ERROR
Device ID : 2 Path ID : 0
Connection ID : 0 Log Instance : 0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

<2004> 1000Base-T in path 0/0/10/0/0
Detected a faulty or disconnected cable.
sunuxap1:[root]:/var/adm

I've open a case with HP support but could not get much advices.

PLease give me some advices on how trobleshoot this issue or what to look for te next time it happens again.

Thanks in advance!
Tom

Re: cannot telnet to server

B. Hulst — Thu, 14 Jun 2007 16:01:42 GMT

Hi,

Check for the number of open files in the kernel and the amount the system is actually using. With glance for example.

Also check if there are not too many connections still left open. With "netstat -a".

Regards,
Bob

Re: cannot telnet to server

tom quach_1 — Thu, 14 Jun 2007 17:38:17 GMT

Hi Bob,

in glance where could i see the open files.

Check for the number of open files in the kernel and the amount the system is actually using. With glance for example.

maxfiles 2048 - 2048
maxfiles_lim 4096 Y 4096

Also check if there are not too many connections still left open. With "netstat -a".
would you be more specific. i did a line count and it return with 1099.
#netstat -a |wc
1099 6823 94270

what am i looking in netstat -a

Please advice!
Regards,
Tom

Re: cannot telnet to server

Noble Sebastian — Thu, 14 Jun 2007 18:51:23 GMT

Hi Tom ,

You can check number of open files

sar -v 1 1

pls check how many lan card is there ?
Which is activated ...check gateway ..?

Now it is working ...?

Re: cannot telnet to server

tom quach_1 — Thu, 14 Jun 2007 19:30:16 GMT

Thanks Noble

the parameter : nfile

...but would it have anything to do with
--NETWORK BOTTLENECK

Regards,
Tom

Re: cannot telnet to server

Noble Sebastian — Thu, 14 Jun 2007 20:07:57 GMT

Hi tom ,
If something was wrong with inetd -

You could try re-creating your inetd.conf file:

mv /etc/inetd.conf /etc/inetd.bak

cp - p /usr/newconfig/etc/inetd.conf /etc/inetd.conf

Modify any settings particular to your environment.....?

regards
Noble Sebastian ...

Re: cannot telnet to server

tsf_1 — Fri, 15 Jun 2007 04:26:42 GMT

What is the exact error when you try to telnet?..as the error will give you better hint.
Check if the telnet daemon is listening; below show its listening:
# netstat -a |grep -i telnet
tcp 0 0 *.telnet *.* LISTEN

Re: cannot telnet to server

Torsten. — Fri, 15 Jun 2007 04:52:32 GMT

How about this message:

<2004> 1000Base-T in path 0/0/10/0/0
Detected a faulty or disconnected cable

Could be a bad NIC, cable or switch port.

Re: cannot telnet to server

Tor-Arne Nostdal — Fri, 15 Jun 2007 07:35:44 GMT

Hi Tom
If you can't find any obvious errors in the server itself, but only have connection problems... it could be a reverse dns lookup problem.

See/Search similar threads on this forum

/Tor-Arne

Re: cannot telnet to server

tom quach_1 — Fri, 15 Jun 2007 10:27:17 GMT

Dear all,

Thanks for your reply.

i think somehow the telnet connection has something to do with error
--NETWORK BOTTLENECK

would someowe gives me me a hint of what to look for?

the erro
<2004> 1000Base-T in path 0/0/10/0/0
Detected a faulty or disconnected cable.
was happened 2 days before the incident, so i would not count it.
Regards,
Tom

Re: cannot telnet to server

Mridul Shrivastava — Fri, 15 Jun 2007 21:58:00 GMT

Hi Tom,

Have you checked the network patches and network interface driver version, are they latest...

Sometime it could be a result of improper handling of driver or patch..

Re: cannot telnet to server

Safarali — Sun, 17 Jun 2007 07:50:22 GMT

Hi Tom
restart inetd -c

Regards
Safar

Re: cannot telnet to server

Safarali — Sun, 17 Jun 2007 07:51:15 GMT

Hi Tom
restart inetd -c
and not working what is the out put of telnet o (zero)
can you login using telnet zero

Regards
Safar

Re: cannot telnet to server

tom quach_1 — Sun, 17 Jun 2007 12:38:41 GMT

Thanks all for your help.

the telnet connection is working fine. it just happenned 2 time that users could not connect.
my question is i just want to know the causes
and how to prevent it from happening again.
after i was able to connect to the server. ran glance and saw in the history these messages

--NETWORK BOTTLENECK
--NETWORK BOTTLENECK .

WHAT WOULD BE THE CAUSE OF THIS ALERT.

Thanks in advance.
Tom

Re: cannot telnet to server

skt_skt — Sun, 17 Jun 2007 21:58:50 GMT

1.Check the network performance chart/statistics(using perfview) to identify if there is any packet storm happened. Example if the normal trend is 2K and it it increases sundeenly to 60K, 80K or higher is a symptom of a possible storm.

2.Check with your network team if there isa ny error reported on swith ports.

3.When the server was not reachable , was the console connection is also disturbed.? (Are both the server IP and console configured on the same swith).

4. Enable a netwrok logging (using nettl)from UNIX level so that you will be able capture the network related errors.