Topic: Loosing connection on external interface

[Holger]

I'm getting _very_ frustrated with my current situation....

I just found out about e-smith a few months ago - and ever since I've been telling _everyone_ how it's the greatest thing since sliced bread.

Now every 2 to 5 days my server looses connection to the outside world. Rebooting fixes my problem temporarily and so does a quick 'ifdown' 'ifup'.

What I need is a few pointers about where to look - I'm sorry but I don't know much about Linux networking. I do now something about the various network protocols and i _have_ applied the DHCP fix for the problem described in the BUG section.

Data: sme 5.1.2 + update + DHCP fix
 - running as both server and gateway

Any hints will be greatly appreciated

[Des Dougan]

Have you checked whether your ISP is having problems with your link (assuming it's a permanent one - your posting doesn't say)? You could also swap your internal and external interfaces to determine whether your network card is faulty.

Des Dougan

[Holger]

Quoting Des Dougan :

> Have you checked whether your ISP is having problems with your link

I'm not 100% sure about that. I do suspect my ISP of being partly incompetent -
but I need proof  
A thesis could be that one DHCP request kills the link and the next revives it.
But again, I'm very new in this area so I don't know how to determine this.

eth1 is connected by a short cable to a hub - just to rule out electrical
problems. The hub is connected by a long cable (30 m.) to my cable modem.

I don't think it's the modem, since powercycling it doesn't help anything.

> (assuming it's a permanent one - your posting doesn't say)?

It is - sorry!

> You could also
> swap your internal and external interfaces to determine whether your
> network
> card is faulty.

Can I do that from the server configuration util?

> Des Dougan

Thanx for the input!

Holger Bille

Holger wrote:
>
> I'm getting _very_ frustrated with my current situation....
>
> I just found out about e-smith a few months ago - and ever
> since I've been telling _everyone_ how it's the greatest
> thing since sliced bread.
>
> Now every 2 to 5 days my server looses connection to the
> outside world. Rebooting fixes my problem temporarily and so
> does a quick 'ifdown' 'ifup'.
>
> What I need is a few pointers about where to look - I'm sorry
> but I don't know much about Linux networking. I do now
> something about the various network protocols and i _have_
> applied the DHCP fix for the problem described in the BUG
> section.
>
> Data: sme 5.1.2 + update + DHCP fix
>  - running as both server and gateway
>
> Any hints will be greatly appreciated
>
>

[leon]

I am running the SME 5.1.2 also and I had the same problem.  I spoke with my cable provider and was told to disconnect the power to the cable modem and also disconnect the coax cable at the back of the modem.  Reconnect the coax, reconnect the power and the internal modem software will seek and retrieve a dhcp address from the provider. Also, it will update the isp's database as to the MAC address of your network card.

[leon]

I am running the SME 5.1.2 also and I had the same problem.  I spoke with my cable provider and was told to disconnect the power to the cable modem and also disconnect the coax cable at the back of the modem.  Reconnect the coax, reconnect the power and the internal modem software will seek and retrieve a dhcp address from the provider. Also, it will update the isp's database as to the MAC address of your network card.

[Randall]

Bare with me as I explain what I found fixed my connection problem here:
 I was running Linux server distribution from Netmax. After about the first year I started losing my connection and forcing a reboot.  I thought the hardware was at fault.  I did not get very far with my Cable provider. So after 2 years of faithful service I replaced my linux server/gateway with  a Linksys firewall/router.   It too failed every few days. I contacted Linksys.  They were working on the problem.  I installed the patch a week later and have not been off line since. The patch consisted of adding a function to set the  MTU ( Maximum Transmission Unit.  Which is the largest unit of data that can be sent on a given physical medium).    I guess it is required with some DSL services as well.  The default is 1500 for Cable.
Man, I hope this helps Somebody.

-Randall

[Holger]

Thanks for the input to all of you!

I will try the thorough powercycling (plus disconnect the coax) of my cable modem even though I have very little confidence in that solution. I'll try anything to at least rule it out.

The MTU issue might be what I'm looking for. I know MTU on ethernet is 1518, which is 1500 IP frame size. Is this something I can configure through Linux?

I'll also try to replace my NIC even though that means loosing my permanent public IP. (My ISP requires that I obtain even static public IPs through DHCP - otherwise the channel is closed)

[Randall]

Manually configure your current  mac address as the mac address of the new card.  That way you do not have to worry about losing your static IP.  If I can find the how to I will email it to you, or post it.