router periodically blocking server

personal_tek · 07-24-2008, 03:16 PM

This is kind of a crazy issue, but I am stumped and I could use an idea.
So, please help if possible.

I have a private network - actually 2 networks combined - 192.xxx.xxx.xxx and 172.xxx.xxx.xxx connected by a router. I don't know why they didn't just make it all a 172 network when they added that, but i wasn't here then.

anyway, on the 192 side i have a linux server that serves a specific app. the computers that access the app are all on the 172 side of the router.

about every 5-8 hours, the computers that access the server lose their connection to the server - all of them lose the connection simultaneously. they can't ping the server at all. they CAN ping anything else on the 192 side. and they can ping other 172 systems.

rebooting the router fixes the problem, but i don't want to get called in at 3:42 am to come in and reboot the router.

the first thing that entered my mind is an ACL on the router, but i think that would block it all the time and not just every once in a while.

i considered a problem with the server itself or the nic in the server, but that doesn't pan out because i can ping from the same side of the router that the server is on.

i recently made some changes to my DNS setup (i set up OpenDNS), but I don't think that is it. I can do nslookup on the server name and it resolves to the static ip on the server just fine.

so, if you have any suggestions, please shoot them my way.

much thanks!

07-24-2008, 03:16 PM	#1 (permalink)
personal_tek Registered User Join Date: Sep 2004 Posts: 47 OS: 98/XP/Linux	router periodically blocking server This is kind of a crazy issue, but I am stumped and I could use an idea. So, please help if possible. I have a private network - actually 2 networks combined - 192.xxx.xxx.xxx and 172.xxx.xxx.xxx connected by a router. I don't know why they didn't just make it all a 172 network when they added that, but i wasn't here then. anyway, on the 192 side i have a linux server that serves a specific app. the computers that access the app are all on the 172 side of the router. about every 5-8 hours, the computers that access the server lose their connection to the server - all of them lose the connection simultaneously. they can't ping the server at all. they CAN ping anything else on the 192 side. and they can ping other 172 systems. rebooting the router fixes the problem, but i don't want to get called in at 3:42 am to come in and reboot the router. the first thing that entered my mind is an ACL on the router, but i think that would block it all the time and not just every once in a while. i considered a problem with the server itself or the nic in the server, but that doesn't pan out because i can ping from the same side of the router that the server is on. i recently made some changes to my DNS setup (i set up OpenDNS), but I don't think that is it. I can do nslookup on the server name and it resolves to the static ip on the server just fine. so, if you have any suggestions, please shoot them my way. much thanks!