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Richard Hall
Richard Hall, Certified Networking Engineer
Category: Networking
Satisfied Customers: 249
Experience:  Chief Information Officer at Spectrum Contracting Serv.
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I have multiple Netopia 3347 routers connected to AT&T using

Customer Question

I have multiple Netopia 3347 routers connected to AT&T using static IP addresses. The routers periodically lock-up. Then, when rebooted, they run fine again for 2-18 hours. What are all the potential causes of a lock-up?
e.g., DOS attack and logs fill up, etc.
Submitted: 2 years ago.
Category: Networking
Expert:  Richard Hall replied 2 years ago.
Hello my name is ***** ***** networking settings, are you using each router on the same subnet? I.E.,Richard
Customer: replied 2 years ago.
No....all are independent locations.
Expert:  Richard Hall replied 2 years ago.
Sounds like a network collision of some kind.....Can you tell me each router and it's network settings?
Expert:  Richard Hall replied 2 years ago.
Just the basics, router a- ip address router b ip address etc...
Customer: replied 2 years ago.
No.....I'm not able to disclose those. I don't think there's a collision issue as they work fine for quite some time after a cold boot. I wanted to know the theoretical reasons this netopia router 3347, might lock up. E.g., too many failed external authentication attempts, or the logs fill up from attempts, etc. What are the list of theoretical reasons that a 3347 might lock up, assuming no contention?
Expert:  Richard Hall replied 2 years ago.
Dig into your logs. I'd keep them cleaned up, but i can't see this causing the problem.But they may get you some insight. I would suspect a couple things, DNS attacks, something causing multiple network collisions(which you can view at the switch). Another thing I would try if there is a lot of external traffic, it could be a networking resolution issue for one of your services being used.I don't know about your DNS settings, but add a couple of additional dns servers and/or change your primary. Do you use VPN services over the network? Richard
Expert:  Richard Hall replied 2 years ago.
In addition, if you are not using a hardware firewall like vyperwall or something to handle that traffic, if you are getting slammed, then I would employ one. Identify the offendors(which your logs may already show you) and start blacklisting the most egregious offenders.
Expert:  Richard Hall replied 2 years ago.
Since you know linux, they make some great firewalls as well. That's what I prefer over the out of the box firewalls.Can't beat linux for a firewall IMO.
Customer: replied 2 years ago.
AT&T has already verified all of that.....they are researching the logs and all the packet capture we've sent them. They have an open ticket.I was just hoping to find out the theoretical reasons this particular modem 3347, might lock up if all the other networking items are fine.....e.g., things internal to the modem.....why they would be working fine and suddenly quit. They had been working fine for years until last week when the lockups started. AT&T applied a firmware upgrade, but, after we began having problems, backed that off. We're still having problems with the old firmware that has functioned well for a long time. Thanks.
Customer: replied 2 years ago.
It requires a hard boot. Once done, it works fine again for a few hours. Almost implies a memory leak or some resource contention/overflow......
Expert:  Richard Hall replied 2 years ago.
I was going to ask about a firmware upgrade. Is there a way to back off the current upgraded firmware to a prior version even, and then reinstalll the proper firmware that had been working all the time.That is what I would try to do first. Richard
Customer: replied 2 years ago.
That's what was done, yet the problem persists.Thanks!
Expert:  Richard Hall replied 2 years ago.
Well, I would also make sure you are not dropping signal with your isp. That would do it.
Expert:  Richard Hall replied 2 years ago.
Logs should tell you that. memory leaks, I would doubt. As far as rolling back, i was talking about rolling back even another step. Prior Version(never Installed per scenario) <InstallCurrent Version Roll backUpgraded Version: Upgraded didn't work rolled back to current version.
Customer: replied 2 years ago.
Expert:  Richard Hall replied 2 years ago.
You are welcome.Richard