Share your knowledge at the LQ Wiki.
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 05-27-2009, 03:19 PM   #1
LQ Newbie
Registered: May 2009
Location: Hungary
Distribution: suse
Posts: 6

Rep: Reputation: 0
VLAN, Bridge, Route - Cant get my head around it

Hi guys,

I have the following setup:
Two sites with one Internet access.
At one site
ISP modem with VLAN3023, and VLAN3024 - Router (VLAN3023/, mask,VLAN3024/one public ip address/,eth0/ mask - subnet

Other site
Modem with the other end of VLAN3023 - Router (eth0/ mask, eth1/ mask

At the first site I use masquerading to connect to the internet.
I can ping and traceroute any public internet ip or name from any of the sites. the interfaces in the network can ping each other, but i can not ping from or vica versa.

What am i missing here?

here is a lame network topology drawing to help.
Modem 1            Router 1
|---------|   |-----------------------|
|VLAN3024 |   |VLAN3024 x.y.245.234/30|
|         | - |VLAN3023| - subnet
|VLAN3023 |   |eth0  |
|---------|   |-----------------------|
Modem 2 |         Router 2  
|--------|   |---------------------|
|VLAN3023| - |eth0  |
|--------|   |eth1| - subnet

Last edited by acid_kewpie; 05-27-2009 at 04:36 PM.
Old 05-31-2009, 05:49 PM   #2
LQ Newbie
Registered: May 2009
Distribution: debian
Posts: 12

Rep: Reputation: 0
additional information

I see no obvious mistake here.

In order to troubleshoot this setup, it would be useful to see where the packets are stuck.

Could you post the results, while pinging from, of:

on router 1: tcpdump -n -i <name of your interface in 3023> icmp
tcpdump -n -i eth0 icmp
route -n

on router 2: tcpdump -n -i eth0 icmp
(I assume eth0 is in 3023 without any vlan tagging)
tcpdump -n -i eth1 icmp
route -n

I think this will help to understand where the packets are blocked.

Also, can router 2 ping And can router 1 ping


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
Performance issue with VLAN + Bridge + TAP AFI Linux - Networking 3 08-14-2008 08:37 PM
VLAN configuration - native VLAN and setting PVID kumarwaiting Linux - Networking 0 07-24-2006 02:51 AM
Linux Bridge Vlan Query switch SNMP christopherccv Linux - Networking 2 05-15-2006 10:12 PM
I am not able to add a new route to my route table using route command prashanth s j Linux - Networking 2 09-03-2005 04:34 AM
x86 Solaris 9 XSun and Matrox G550 dual-head... one head down, one to go. finegan Solaris / OpenSolaris 4 03-11-2003 12:39 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 10:05 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
Open Source Consulting | Domain Registration