How do I understand eth0 and eth1?

[max renn]

I am trying to understand how kubuntu differentiates between the two nics. I have my local network on eth1 and our Internet on eth0. I want everything in kubuntu to understand that eth1 is OK and anything and everything is allowed. I want everything in kubuntu to understand that eth0 is the Internet and so only certain things can happen there.

Example: I install moblock and it is blocking on both nics. I install CIFS and it does not detect my network shares.

Are these issues specific to each installed program? Is there a communal area in kubuntu that allows me to to dictate my needs. Or, is it a mixture of both?

Kernel IP routing table
Destination   Gateway     Genmask     Flags Metric Ref  Use Iface
10.0.0.0    *        255.255.255.0  U   0   0    0 eth1
192.168.0.0   *        255.255.255.0  U   0   0    0 eth0
link-local   *        255.255.0.0   U   1000  0    0 eth1
default     192.168.0.1   0.0.0.0     UG  100  0    0 eth0

[mhauber]

Re: How do I understand eth0 and eth1?

Why not just use shorewall? There are examples on how to set up computers with two NICs here: http://www.shorewall.net/two-interface.htm

The example is mainly for routing between external and internal NICs, but if you yank the routing part out of it, you'll have what you seem to be asking for.

Personally, I prefer the "block-drop all by default" approach because that's just the way I was taught (still not able to apt-get install PF, btw ). If you go that route as well, you'll need to allow for each service that your computer needs access to or wants to provide.

If you want something more simple to use (GUI stuff), there's firestarter and a few others I believe. I read somewhere about a web-based control for shorewall called webmin, but haven't messed with it.

HTH


mhauber