illegal packets

Hi,

I keep getting this invalid packets, one to five per minute.

Why are the invalid ?

cu romal

Message from syslogd@gateway at Feb 16 20:39:27 ...

kernel: nf_ct_tcp: invalid packed ignored IN= OUT= SRC=212.60.137.183
DST=217.72.204.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25024 DF PROTO=TCP SPT=52369 DPT=80 SEQ=4686532 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A0244

Feb 16 20:39:27 gateway kernel: nf_ct_tcp: invalid packed ignored IN= OUT= SRC=212.60.137.183 DST=217.72.204.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25024 DF PROTO=TCP SPT=52369 DPT=80 SEQ=4686532 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A0244

Message from syslogd@gateway at Feb 16 20:39:33 ...

kernel: nf_ct_tcp: invalid packed ignored IN= OUT= SRC=212.60.137.183
DST=217.72.204.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25025 DF PROTO=TCP SPT=52369 DPT=80 SEQ=4686532 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A0245

Feb 16 20:39:33 gateway kernel: nf_ct_tcp: invalid packed ignored IN= OUT= SRC=212.60.137.183 DST=217.72.204.254 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=25025 DF PROTO=TCP SPT=52369 DPT=80 SEQ=4686532 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT (020405B40402080A0245

This is a connection-initiating SYN packet, but there is an existing connection already between 212.60.137.183:52369<->217.72.204.254:80. So the firewall ignores the packet (does not take it into account at keeping track the connection, but lets it through). Probably it's a connection-reopening, which is not handled properly.

The newest git tree contains a fix for reopening connections. So either upgrade or ignore the invalid packet warnings ;-).

Best regards,
Jozsef
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E-mail : [email protected], [email protected] PGP key : http://www.kfki.hu/~kadlec/pgp_public_key.txt
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Hi Jozsef,

thanks for your fast reply.

As newer kernels as 2.6.24 aren`t supported in OpenWRT I have to ignore it for the moment :-(

For the moment I have to remove the INVALID statement from my configuration for the recent-module, as recent puts this invalid packets on the blacklist.

cu romal