Help please: Connections to my server keep dropping!

[JasonGW]

I've been having a problem for awhile now and it's driving me up the wall. I thought it was my cheap Belkin router, so I replaced it with the fabled Linksys WRT54G in hopes that the problem would go away, but it doesn't. Some detail:

2003 Server, Domain Controller (DNS server, DHCP server)-->WRT54G on internal interface (no default gateway, first in Connections list), directly on Internet via second internal interface (default gateway, second NIC in Connections list).

WRT54G-->DSL connection on WAN, Server on LAN ports, 2 client PC's via 802.11g

Domain User accounts with redirected My Documents (Offline files enabled)

Every few minutes at random intervals, I get the "You are no longer connected to [servername]" error message and the system begins working offline. In this condition I cannot access my DFS root. RDP connections work fine and are stable, and if I simply right click the offline files icon and choose "Synchronize" the problem disappears for awhile. The WRT54G is acting solely as my router, there is no DHCP running on it. I have also updated it to the latest firmware (1.00.09, if I recall) which is supposed to resolve an "internal DNS server" issue. My own server reveals no errors in the logs whatsoever, and a DNS check passes instantly every time. Extended logging reveals no errors.

Any help would be greatly appreciated, thanks!

Jason

[tain]

So the only service that loses connectivity is DFS, right? Everything else, including internet access, is OK?

Are you using the router's firewall? Any port forwarding?

[JasonGW]

So the only service that loses connectivity is DFS, right? Everything else, including internet access, is OK?

Are you using the router's firewall? Any port forwarding?

Yeah, I have the router's firewall (NAT) running for network connection sharing purposes. What happens is that offline files loses connectivity, and DFS does at the same time. Manually synchronizing fixes both issues. This doesn't affect internet connectivity at all, nor even my RDP connection from my desktop to the server itself, interestingly enough. It's as though the router doesn't want to do routing for *internal* machines.

Any clues would really help.

Thanks!

Jason

[tain]

How strong is your wireless strength? Have you tried a different channel? A dropped signal can cause odd client issues like this.

The client PC logs don't reveal anything? If not, change your auditing to reflect these connectivity issues.

[RogueSpear]

It would not surprise me that you're not losing your RDP connection. RDP seems to have become far more tolerant of crappy connections over the years. On the other hand, the offline files feature seems to spring to life at the drop of a hat for me sometimes.

But back to the topic.. you should have a default gateway set for every interface. I'm still a little confused regarding your topology however. I guess I'm one of those types who needs the pretty illustrations to get it

[JasonGW]

How strong is your wireless strength? Have you tried a different channel? A dropped signal can cause odd client issues like this.

The client PC logs don't reveal anything? If not, change your auditing to reflect these connectivity issues.

My wireless strength is *excellent* in every room of the house. I've tried every channel from 1-11 unsuccessfully. I haven't tried my PC with a cable to see if it still happens, but ultimately I want to be wireless regardless so it's kind of immaterial except perhaps for isolation purposes. The logs so far show only "disconnected" and "reconnected". I'll see if I can find something better later on when I get home.

Jason

[JasonGW]

It would not surprise me that you're not losing your RDP connection. RDP seems to have become far more tolerant of crappy connections over the years. On the other hand, the offline files feature seems to spring to life at the drop of a hat for me sometimes.

But back to the topic.. you should have a default gateway set for every interface. I'm still a little confused regarding your topology however. I guess I'm one of those types who needs the pretty illustrations to get it

Well I've tried my server with default gateways at both interfaces, which Windows tells me is a non-no, but that didn't help either. All my PC's are being given the default gateway of the router itself (192.xxx.xxx.1), since that's the outbound internet connection.

I'll see if I can't whip up an illustration, LOL

Jason

[tain]

The illustration should help. RogueSpear is right that your topology is a bit confusing.

[JasonGW]

The illustration should help. RogueSpear is right that your topology is a bit confusing.

yeah, as I was putting this together it started to make less sense to me, even, LOL. Somehow it made sense at the time.

[RogueSpear]

If your server is consuming the IP address allocated to you by your ISP, then your other clients shouldn't have internet access. Now this is just a suggestion, but I wouldn't have my server naked facing the internet. I would hook up the server to the WRT54G, assign it a static IP, and then create some port forwarding rules if you're doing something like hosting a web site.

The way it is now, one of two things is going on. Either what I described above, the server is consuming the IP from your provider, or you have it assigned a 192.168.x.x address on both NICs. If it's the latter, then it would seem as though you have a circular route problem since the server is hooked into more than one demarcation point but both interfaces are part of the same subnet.

You should be able to get rid of the 10/100 switch unless you need it for physically reaching someplace in your house.

[JasonGW]

If your server is consuming the IP address allocated to you by your ISP, then your other clients shouldn't have internet access. Now this is just a suggestion, but I wouldn't have my server naked facing the internet. I would hook up the server to the WRT54G, assign it a static IP, and then create some port forwarding rules if you're doing something like hosting a web site.

The way it is now, one of two things is going on. Either what I described above, the server is consuming the IP from your provider, or you have it assigned a 192.168.x.x address on both NICs. If it's the latter, then it would seem as though you have a circular route problem since the server is hooked into more than one demarcation point but both interfaces are part of the same subnet.

You should be able to get rid of the 10/100 switch unless you need it for physically reaching someplace in your house.

It is consuming *an* IP from my provider, but that's OK, I have four statics. That's the entire reason that there's the switch in between the DSL modem and the WRT54G. Both have external IP's of 66.159.238.xx, each with its own. The internal interface of the WRT54g is 192.168.0.1, since it's the default gateway for all clients, and the server's internal IP address is 192.168.0.102. The clients are on DHCP. In a change from when I originally posted I now allow the WRT54G to do DHCP, but that doesn't seem to be helping at all.

Of course I don't have the server naked, though, I've got a firewall on it, and of course I've locked down everything but the needed ports for that interface. Ack.

Jason

Edited August 25, 2006 by JasonGW

[CptMurphy]

Why DON'T you have the server behind the router? Doesn't that router have a feature to assign the DMZ? If it does, set it to the server's internal port

[JasonGW]

Why DON'T you have the server behind the router? Doesn't that router have a feature to assign the DMZ? If it does, set it to the server's internal port

I want the server and the router on separate IP's for various reasons.

Jason

[RogueSpear]

Ok, knowing that you have multiple static IPs assigned to you makes all the difference in the world. I had ASSumed that you were only provisioned one

Providing that you are using an unmanaged (or dumb) switch - your typical consumer level switch - then it should make no difference whether or not you use it. I still contend that you should configure a default gateway on all possible interfaces and hopefully this will make a difference for you.

Give the internal interface of your server a default gateway of the WRT54. Give the WRT54 a default gateway of the routers internal address. Personally, I would use the WRT54 as a DHCP server for your clients since it's on the same subnet. I don't know for certain that Linksys products will forward DHCP traffic (broadcast) between subnets. And even if it does, it's totally unnecessary. You can still configure it to assign DNS server assignments to your server.

I don't know if I mentioned this in a previous post or not, but I've experienced difficulties when a default gateway is not assigned where one would normally be expected. Even if you feel as though it's not necessary, like traffic should never need to flow in that path, it definately makes a difference. Remember, you're dealing with all kinds of different vendor equipment here between server, router, NICs and so on. Not all networking hardware manufacturers are equal in the way they do things. So I always make it a practice to dot all my I's cross all my T's.

[tain]

I don't know for certain that Linksys products will forward DHCP traffic (broadcast) between subnets.

I don't think they will, but am not certain. They shouldn't. A DHCP Relay Agent is appropriate.