Topic: Same subnet mask on both NIC?

[trenskow]

Hey again

My network is setup like this

DVG-1120S > SMEServer > clients

now, is it possible to have the same subnet mask on both NIC of the SMEServer, so that the DVG gives smeserver an IP address with subnet mask 255.255.255.0, and the SMEServer gives the clients a an ipaddress with the same subnet mask.
The reason for this question, is, that i had done it, but then my server went crazy, CPU used 100? alle the time because  S16adjust-masq, S55email-conf, S80pptpd-conf, S55mailfront-co, S47proftpd-conf, S50conf-securit, S85update-dns always was restarting.

When i look in /var/log/dhcpd/current

it says somewhere
Multiple interfaces match the same subnet: eth0 eth1
Multiple interfaces match the same shared network: eth0 eth1
Listening on Socket/eth0/192.168.19.0
Sending on   Socket/eth0/192.168.19.0

Is there anyway around this?, or do i have to give them different subnet masks?

[arne]

I think there will be no problem to have the same subnet mask on both sides.

But it wil need to be to different network numbers on each side of the router.

10.0.0.5/255.255.255.0 and 10.0.0.100/255.255.255.0 will not work, while

10.0.0.5/255.255.255.0 and 10.0.1.100/255.255.255.0 will work (Networknumber 10.0.0 and 10.0.1)

Of cource also something like 152.95.78.24/255.255.255.0 and 10.0.0.1/255.255.255.0
wilwork (If this is the correct external mask)

[trenskow]

I have tried from DVG to Smeserver 192.168.0.10/255.255.255.0 and from Smeserver to client 192.168.20.65/255.255.255.0

and that did not work..
well, the functions of the server works fine, i can surf, reveive mail etc.
But the CPU load is constantly at 100% because of the procceses i wrote before is "restarting"

but if i give 192.168.0.1/255.255.240.0 and 192.168.20.65/255.255.255.0 the cpu is at normal load.

anyone knows why this happen, that the cpu load is at 100% when both NIC are on the same subnet adress