understanding iptables logging

Kareem Shehata kareem-d+8TeBu5bOew5LPnMra/2Q at public.gmane.org
Mon Jul 5 23:23:03 UTC 2004

On Mon, 2004-07-05 at 18:58, daniel wrote:
> i have a series of lines in /var/log/messages looking like this:
> Jul  5 18:53:26 fightclub kernel: [DROPPED (IN-eth0)]: IN=eth0 OUT= 
> MAC=00:30:bd:1c:e0:a7:00:05:00:e3:ec:d6:08:00 SRC= DST=<myIP> 
> LEN=48 TOS=0x00 PREC=0x00 TTL=106 ID=5656 DF PROTO=TCP SPT=3770 DPT=9898 
> WINDOW=16384 RES=0x00 SYN URGP=0
> and it's kinda hard to google for "iptables df" so i was hoping someone here 
> could explain just what all of the above abbreviations are.  here's what i've 
> got so far:

The fields are all taken directly from the IP header.  In this case, I'm
guessing DF means that the Don't Fragment bit is set.  Here's a quick
guide to the rest of it:




   kareem-d+8TeBu5bOew5LPnMra/2Q at public.gmane.org   -    Kareem Shehata     -     416-766-4911     
      The most exciting phrase to hear in science, the one that
      heralds new discoveries, is not "Eureka!" (I found it!) but
      "That's funny ..."
        -- Isaac Asimov

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