Troubleshoot 3COM 3001 NBX ip_unknown problem

Posted on 2011-03-22
Medium Priority
Last Modified: 2012-10-26
Hello my friends...

Things are getting pretty desperate here...

My 3001 NBX from 3com (R6_5_20) has been working perfectly for months... Now it works for more or less an hour and then all the phones in the branch offices (one connected in wi-fi, 1 km distance and others using adsl and vpn) go to ip_unknown and stop working. Phones in central office never stop working, anyway.

If I reset the nbx everything starts to work again but then after more or less an hour they're dead again. Even when I have the problem I'm able to ping branch offices and use applications without problems so it must be something related to the nbx or the astaro security gateway 7 that connects the wi fi bridge and lets vpn client reach our network. I just do not have diagnostic clues because from a "normal network" point of view the situation's normal.

Any hints about what I could do to find and solve the problem?
Question by:ltpitt
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LVL 32

Assisted Solution

DrDamnit earned 900 total points
ID: 35197732
First thing I would check is can you restart any firewalls and have it fix the problem. The reason is, the SIP registrations can eventually time out and re-register. Over time, the NAT tables fill up, and the stateless packet inspection fails causing remote phones to just... check out.

Next time you have this issue, try restarting the firewall to see if that fixes the issue. If it does, then it may be a firewall issue.

Author Comment

ID: 35198006
Oh, great!

So, if I've understood correctly, when my phones will go to ip_unknown instead of resetting my nbx I should reset my firewall, right?
LVL 32

Expert Comment

ID: 35198543
Yes. Exactly.
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LVL 32

Expert Comment

ID: 35220651
Did you try this? Did it work?

Author Comment

ID: 35276212
Hello my friend!

I'm sorry for taking a little longer: the problem didn't show in a week.
Now it has come back and I've tried resetting the firewall instead of the nbx: no luck...
The phones remained in ip_unknown :(

Resetting the nbx took everything back to a working situation...
LAsting for more or less one hour: phone in our company never stopped working, anyway: just those in branch offices.

What could I check?

Accepted Solution

ltpitt earned 0 total points
ID: 38491570
I have the final answer for this!
I am sorry if it took ages but I didn't have credit to log in in expert exchange until now.

My wireless bridge was weak: that's why my phones kept on getting lost.

Packets were lost in the communication: fixing the bridge did the job.

Author Closing Comment

ID: 38537825
The answer from the other user pointed me in the right direction but it wasn't a detailed solution.

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