Hello, I have a server which has 3 network adapters. 2 internal or local network and 1 connected to a cable modem Motorola Surfboard provided by my ISP.

The network adapters are all RTL8168b/8111b and are using driver r8169 (2.3LK-NAPI). The system is running a custom kernel 2.6.39 and of course everything works, but once in 2-3-4-5 or even more days the connection between my network adapter connected to the cable modem fully dies, without any error.

Normally you can connect to the cable modem using an ip address 192.168.100.1, but when the connection dies between the network adapter and modem, this ip can't be reached anymore even if the network cable is fine and everything theoretically should work.

The fix in a case like this is to fully reboot the server, nothing works, restart dhclient, the network, putting eth0 (the network adapter connect to the modem) and brining it up again doesnt do anything.

This issue it's happening for at least 6 month and my ISP says it's my fault. Before having all the network adapters RTL8168b/8111b, the adapter connected to the modem was a different one, but still was happing the same thing. Does anybody know what could be the idea or what I could do to fix this?

NOTE: Restarting the cable modem also doesn't help. Unplugging the modem doesnt help either.

Im really out of ideas and this problems doesn't go away at all. Please if any of you know what could be the issue, post it. I really need to fix this.

Info about the cable modem:

Software Version: SB5100E-2.3.6.0-SCM00-NOSH
Hardware Version: 3
MIB Version: II
GUI Version: 1.0
VxWorks Version: 5.4

Can you try setting a static IP? Also when connection dies, try to unload/load nic module, this might give some errors.
Hope that helps.

I cant. All the network adapters are the same using the same module. I'm using a static ip address and was using dhclient before still the same issue. The only fix before and now, reboot.

Since you mentioned you are using custom kernel, have you tried if the issue is happening on stock kernel as well?

Why you're using a none LTS version of Ubuntu for your server?

Have you check your cable RJ45 ?

and ... When the conection is down ?

I didnt check or dont remember if i've checked with the stock kernel, but this means to boot into the stock kernel and wait.
Yes I have tried to restart the network, nada!

Any firewall configuration of the Motorola Router ?

There must be something that you're not mentioned... The conection cant turn off itself...

Well this is the point, if this would happen every time at the sametime, then I would say it's some configuration.
But this happens randomly usually after 2-3 days of uptime.
There is no firewall in the modem, there is no such a thing in this type of modem, or if there is, it's hidden.

So the connection turn's off at the same time after 2 3 days of uptime. ? Can you try to upgrade the kernel or just upgrade if there is any about your network card ? . Becouse it could be some bug of the kernel or something in this version of the Ubuntu. Why you didn't install a LTS version ? I know that Ubuntu LTS versions for servers are very stable of this product.

I prefer Debian, becouse it's the base of Ubuntu and the distro is made for servers and I never seen that kind of error in Debian.


Can you see the syslog, when the connection is down and post it here. To know what happend in the system on that time. That could solve your problem...

No, I said it happens after 2-3 days the connection dies, but it can be 2 days, 4 days or even 7 days. Its random, not precise.
Regarding the kernel, I was running about 5 days ago kernel 2.6.37 and now im running 2.6.39 and the same thing happens. I even rebuild
the kernel a bit different and still the same thing.

When the connection dies between the network adapter and modem, there is nothing, not errors, or something like that, which is why this is harder to fix.

Have you googled it or, search problem like yours in the forums of Ubuntu, becouse they will know better what happends with their Distro. Sorry I cant help you with no log. I usually fix the bugs or errors with the logs of the system.


Best Regards,

Miro

I do the same xsource, that's why I'm writing. If I would have logs, I wouldn't ask questions