Review your favorite Linux distribution.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 10-06-2011, 01:39 AM   #1
LQ Newbie
Registered: Dec 2007
Location: Russia, Moscow
Posts: 4

Rep: Reputation: 0
CentOS Gateway. Packets with local IP are on the WAN interface.

Hello guys!
Throw our billing (using libpcap) I see than on external interface (eth1) on our gateway there are outbound packets with source IP from local network. This is the iptables rule for SNAT:
-t NAT -A POSTROUTING -o eth1 -j SNAT --to-source external-IP
Now I use tcpdump to shiff this packets to show it's content. But I'm confused.
Old 10-06-2011, 04:36 AM   #2
Senior Member
Registered: Oct 2009
Location: Wroclaw, Poland
Distribution: Arch, Kubuntu
Posts: 1,254

Rep: Reputation: 314Reputation: 314Reputation: 314Reputation: 314
Show routing table and content of that packets (without data).
Old 10-06-2011, 04:37 AM   #3
LQ Newbie
Registered: Dec 2007
Location: Russia, Moscow
Posts: 4

Original Poster
Rep: Reputation: 0
Well, I've sniffed this packets and its MAC-s. It's not outgoing but incoming packets from my ISP's gateway. That's strange, but the problem has gone =)


gateway, iptables, snat

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Routing issue (same subnet, 2 wan gateway, 1 webserver) leosophy Linux - Networking 3 09-03-2010 02:15 PM
2 wan in local ybgwon Linux - Networking 2 04-10-2009 12:02 AM
Capturing packets from my WAN/Router {O_o} Linux - Security 4 10-12-2005 04:56 PM
how can i use libpcap to capture packets for the local loopback interface (lo) ? gajaykrishnan Programming 0 02-22-2005 04:03 AM
Two WAN cards on same gateway h8trix Linux - Networking 8 10-28-2004 10:37 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 07:06 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration