RE: DoS problem.

["Steve McLaughlin" <Steve.McLaughlin () aggreko co uk>]

Call the ISP, they can usually isolate it from there...
 

-----Original Message-----
From: Jorge Alfredo Garcia [mailto:frederix () gmail com] 
Sent: 20 January 2006 18:02
To: pen-test () securityfocus com; firewalls () securityfocus com
Subject: DoS problem.

I have two dedicated servers, both hosted by the same provider and
both on the same segmnet.
I am under a denial of services attack but idont know exactaly how to
stop it.
Here is a piece of my netstat output:

tcp        0      1 XX.XX.XX.AA:47561           XX.XX.XX.BB:80        
     SYN_SENT
tcp        0      1 XX.XX.XX.AA:47562           XX.XX.XX.BB:80        
     SYN_SENT
tcp        0      1 XX.XX.XX.AA:47565           XX.XX.XX.BB:80        
     SYN_SENT
tcp        0      1 XX.XX.XX.AA:47564           XX.XX.XX.BB:80        
     SYN_SENT
tcp        0      1 XX.XX.XX.AA:47567           XX.XX.XX.BB:80        
     SYN_SENT

Ok, XX.XX.XX.AA is the server i am in now.
XX.XX.XX.BB is mine two and here are the connections:

tcp        0      0 XX.XX.XX.BB:80              XX.XX.XX.AA:50749     
     SYN_RECV
tcp        0      0 XX.XX.XX.BB:80              XX.XX.XX.AA:50598     
     SYN_RECV
tcp        0      0 XX.XX.XX.BB:80              XX.XX.XX.AA:50309     
     SYN_RECV

I have thousands of this connections on both servers.
I make iptables rules in both sites but the attack still running and
the rules dont work.

I cant understand how this attack can be made taking into account that
the attacker isnt inside any of my servers.
Why iptables rules dont work against this?

Thanx in advance.

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