IP Connectivity

[Karen Hardman]

I am having problems with sessions disconnecting from my HP-UX box.

We have recently changed over to an MSP, and they have allocated us an IP
number, and since we have changed over, we have to keep 'killing' users out of
the system.

The only time I have seen this happen before is when the IP number has been
duplicated.? Since we have not allocated the IP number or the gateway, we
assume that this number has not been duplicated.

Can anybody else give me any ideas as to why my users are getting disconnected
from sessions?

[Paul Winchcombe_1]

I would definitely apply patches first (if possible to get downtime)

You will need LAN DRIVER,STREAMS,ARPA, Telnetd and rlogind patches.

The most common cause of this problem is duplicate ip address or perhaps MAC
address. What networking topology are you using ? Do you specifiy the MAC
addresses at all ?

Is it the same client or various clients that have this problem?

Are there any performance problems on the machine ?

The HP will starting sending probe packets if no data is received after
tcp_keepstart (default is 2 hours)if no response is received the HP will tear
down the connection. So are connections dropped after this time period.
To check tcp_keepstart
/usr/contrib/bin/netttune -l tcp_keepstart

Check /var/adm/syslog/syslog.log


also check timestamp on /var/adm/nettl.LOG00

if it is recent run following

netfmt -nNlf /var/adm/nettl.LOG00 | more

go to end of file (shift-g) and look for a meaningful information (this is the
hard bit). If somebody has same IP address as HP then it will log this here.

The other thing that sometimes works if the remote client is on the same subnet
is to do a broadcast ping and compare mac addresses to ip returned by arp
command.

Clear arp cache
arp -a --- list arp cache
arp -d ip_address --- on each entry

To get subnet broadcast address do following

ifconfig lancard (sorry but chevrons don't work)

Then ping subnet-broadcast

Then save output of arp -a to a file, clear arp cache as above then broadcast
ping and then save new output of arp command. You now have to compare output of
the 2 arp outputs.

What you're looking for is the same ip address belonging to two differnet MAC
addresses.


Hope this gives you a little bit of help, these are usually the most difficult
problems to track down.

Regards

Paul