Understanding log messages from iptables

Question

I have enabled logging with iptables. Now, I need to understand some of the abbreviations.

Feb 23 20:43:08 spiderman kernel [ 2905.992450]: IN=wlan0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:06:25:09:6a:b5:08:00 SRC=192.168.1.100 DST=192.168.1.255 LEN=241 TOS=0x00 PREC=0x00 TTL=64 ID=64564 DF PROTO=UDP SPT=138 DPT=138

What does each of the following mean:

• [ 2905.992450]
• TOS=0x00
• PREC=0x00
• ID=64564
• DF

Any help is appreciated. Thanks.

Answer 1

[ 2905.992450] - kernel timestamp

TOS=0x00 - The Type of Service of the IP packet.

PREC=0x00 - The Precedence of the IP packet.

ID=64564 - The id of the IP packet.

DF - Fragment Flags. Can have "CE" (congestion), "DF" (don't fragment), or "MF" (more fragments are coming).