Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
I have two interfaces on my machine, and what I need to do is to close off eth1 using iptables due to that interface connecting directly to the DMZ on the router. (Snort is listening on the interface, and thats the interfaces only purpose)
The other interface is eth0 and is connected via the router. This is the interface that is to have no restrictions on it at all.
When I use iptables iptables -i eth1 -A INPUT -j DROP. I cannot get a network connection when this rule is in use. The webserver on the box allows no connection and email is not collected, Even though eth1 is specified. Could this be because the system is trying to use eht1 over eth0, if so how can I tell thesystem to use eth0?
Just to be clear:
Eth0 Protected network connection. No constraints or controls are needed.
Eth1 Snort interface, connected to DMZ, needs stealth
Originally posted by MaverickApollo they are both using 255.255.255.0 eth0 ip is 192.168.1.5 and eth1 is 192.168.1.4
If I was to put them on different subnets it would not work would it? The rest of the network is using a subnet of 255.255.255.0.
It won't work this way..What you can do is
1) use different subnets for the cards and leave 255.255.255.0 netmask
2) divide 192.168.1.0/255.255.255.0 into two subnets, one for every interase (requires change of one of the IPs)
Could you tell us what you're trying to do with this config?
Mara is absolutley correct. The Linux Stack will not allow multi-homing of interfaces (unless you are load-balancing, in which case both NICs have the same IP). If two NICs are in the same subnet, Linux will only use one of the interfaces to respond, reguardless of which interface the request came in on. Which can obviously casue problems. Time for some networking 101. Seperate your networks and enable routing if you need to communicate between them.