LinuxAnswers - the LQ Linux tutorial section.
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 02-02-2010, 07:31 AM   #1
LQ Newbie
Registered: Feb 2010
Distribution: Ubuntu, Red Hat
Posts: 3

Rep: Reputation: 0
Logical interface filtering

Hi All,

I have created 2 logical eth interfaces (eth0:1, eth0:2) on my physical interface (eth0). It was my understanding that by assigning the logical interfaces to another network, only the traffic destined for that network would reach the logical interface.

As it turns out, a tcpdump on all three interfaces (eth0, eth0:1, eth0:2) now shows the same traffic regardless of the packet's destination network.

Is this normal behaviour for logical interfaces in linux? Is there a way to configure the kernel to forward only the appropriate traffic to the logical interfaces?

I'm using Ubuntu Server 9.04

Old 02-02-2010, 09:07 AM   #2
LQ 5k Club
Registered: Aug 2005
Distribution: OpenSuse, Fedora, Redhat, Debian
Posts: 5,396
Blog Entries: 2

Rep: Reputation: 905Reputation: 905Reputation: 905Reputation: 905Reputation: 905Reputation: 905Reputation: 905Reputation: 905
tcpdump uses methods at a lower level than the IP level to capture packets. It typically puts the ethernet hardware into promiscuous mode, in order to trap all traffic. You cannot extrapolate anything about the behavior of the logical interfaces from the behavior of tcpdump.
--- rod.


filtering, logical

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
Extending logical volume LogVol01 Insufficient allocatable logical exte swap space umeshsharma Linux - Newbie 4 06-22-2009 12:26 PM
How NET_TX_SOFTIRQ select network interface when multiple interface exits Mr.J Linux - Kernel 0 06-02-2009 11:17 AM
ERROR: The interface does not exist (UBUNTU) interface eth0 not configured anshulbhatt Linux - Networking 2 11-20-2008 12:23 PM
WPA support through 'ndiswrapper' interface is deprecated; use 'wext' interface lavie Linux - Wireless Networking 1 12-04-2006 11:13 AM
Sendmail Spam filtering and Virus filtering MrJoshua Linux - General 2 04-03-2003 10:12 AM

All times are GMT -5. The time now is 04:47 PM.

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