LinuxQuestions.org
Visit the LQ Articles and Editorials section
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Security
User Name
Password
Linux - Security This forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here.

Notices



Reply
 
Search this Thread
Old 07-12-2007, 03:23 AM   #1
DJJoe
LQ Newbie
 
Registered: Jul 2007
Posts: 2

Rep: Reputation: 0
Routing tables mysteriously reloaded


Hi

A few days ago my server suddenly went offline out of the blue, after over a year of uptime. RHEL 4. I could get the ISP to ping it from the switch, but from outside the subnet ping requests were being ignored. The machine was up and running, and when I got to the console I noticed a few "Neighbour table overflow" entries on the console.

After a few hours of struggling, I eventually found that the default route in the routing table was incorrectly set to the IP of the server and not the IP of the gateway. So all packets to the subnet were getting out, but no others. My /etc/sysconfig/network file had an incorrectly set GATEWAY setting, which must have been there since I installed over a year ago (the date of the file pretty much confirms this), and I must have adjusted the routing tables by hand.

I can only think that for some reason the routing tables where suddenly reloaded, and the incorrect gateway was loaded from the /etc/sysconfig/network file. Does anyone know why this might have happened?

I think it's pretty unlikely that I've been hacked (although always possible). The firewall is configured well, very few ports open, and there seem to be no other signs of a hack - I would have expected more than a routing table change / reload in that case.

What could cause the reload? IPTables throwing a wobbly? TCP stack? Kernel? Malicious packets, ICMP or otherwise?

Any suggestions/ideas would be appreciated!
 
Old 07-12-2007, 09:41 PM   #2
Berhanie
Senior Member
 
Registered: Dec 2003
Location: phnom penh
Distribution: Fedora
Posts: 1,625

Rep: Reputation: 165Reputation: 165
Quote:
What could cause the reload?
A power outage? Check uptime.
 
Old 07-13-2007, 04:01 AM   #3
DJJoe
LQ Newbie
 
Registered: Jul 2007
Posts: 2

Original Poster
Rep: Reputation: 0
Quote:
A power outage? Check uptime.
Yeah, good idea, but the machine is in a data centre and had been up for over a year...

The interesting this is that if I hadn't incorrectly configured the /etc/sysconfig/network file, I would never have known that the routing tables were reloaded - OK, to be accurate, I'm *assuming* they were reloaded, as that's not recorded in the logs AFAIK... It's the only explanation I have for why the default route was suddenly incorrect.
 
  


Reply


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 tables props666999 Linux - Networking 1 10-14-2005 09:27 PM
Routing tables TPB Linux - Networking 3 07-27-2005 10:01 PM
IP Routing Tables collern2 Linux - Security 1 05-23-2005 11:48 AM
two routing tables fugzi Linux - Networking 7 12-03-2004 07:02 PM
routing tables help hadoque Linux - Networking 0 08-28-2004 10:10 AM


All times are GMT -5. The time now is 03:24 PM.

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