TL-R600VPN stops working for only one person at a time on a 20+ user network

TL-R600VPN stops working for only one person at a time on a 20+ user network
TL-R600VPN stops working for only one person at a time on a 20+ user network
2013-09-18 03:23:57
Region : UnitedStates

Model : TL-R600VPN

Hardware Version : V1

Firmware Version : 1.2.0 Build 130216 Rel.61471n

ISP : Windstream


This is a very odd problem, and I don't expect anyone will be able to solve it for me, but I'm out of troubleshooting ideas.

I have a network of about 25 users. There are 4 wifi APs that connect to a Cisco Catalyst 2950 switch. The switch connects to the TL-R600VPN, which connects to the Internet.

On a recurring basis, though, one of my users will be unable to connect to the Internet. Everybody else is fine. And it's a different person on different days - it's not just the same person all the time. Here's the scenario:

All of a sudden, they can't get on the Internet. Nslookup cannot resolve hostnames when using an external DNS (8.8.8.8, for example). They CAN resolve hostnames with a DNS on our LAN, but they can't connect to (or ping) anything outside the LAN.

I thought it might be a problem with the AP or the switch, so I connect them directly to a port on the TL-R600VPN. Same result - no Internet access. So I think I've ruled out any problems with the APs or the switch.

If I reboot the TL-R600VPN, everything starts working again for a while, and then the problem recurs. It's like the TL-R600VPN is dropping all their packets destined for the WAN port. All LAN services are still available.

Can anyone think of anything I can check or test to shed any more light on the problem?
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2 Replies
Re:TL-R600VPN stops working for only one person at a time on a 20+ user network
2013-09-18 03:43:09
Right after posting that, I was going through the admin settings one more time, and I noticed there was one entry in Security -> Advanced Security -> Blocked DoS Host List. I've never noticed that before. It was a local DHCP-assigned IP; I don't know if it corresponded to the problem machine, but I'll be able to tell if it happens again. I'll update the thread as soon as I know something.
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Re:TL-R600VPN stops working for only one person at a time on a 20+ user network
2013-09-24 00:16:18
That was indeed the problem.
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