On 07/11/2017 02:23 AM, Vieri Di Paola via Shorewall-users wrote:
> ________________________________
> From: Tom Eastep <[email protected]>
>>
>> This happens when Netfilter believes that flow is closed and deletes the
>> conntrack entry, while one of the end-points still thinks that the flow
>> is alive and sends an RST. In my own ruleset, I handle this with:
>>
>>     RST(ACCEPT)     { SOURCE=all, DEST=all }
>>
>> I have also seen similar problems with SYN,PSH,ACK packets, and added a
>> FIN action in 5.1.5. I use it similarly:
>>
>>     FIN(ACCEPT)     { SOURCE=ALL, DEST=all }
> 
> 
> I added these lines to the rules file:
> 
> RST(ACCEPT)     { SOURCE=all, DEST=all }
> FIN(ACCEPT)     { SOURCE=all, DEST=all }
> 
> and restarted shorewall.
> 
> I'm still getting these in the logs:
> 
> Jul 11 11:07:57 inf-gw1 kernel: Shorewall:dropNotSyn:DROP:IN=enp9s5 OUT= 
> MAC=00:0d:88:cd:7f:c5:00:13:f7:23:ef:b4:08:00 SRC=216.58.214.163 
> DST=192.168.100.2 LEN=1140 TOS=0x00 PREC=0x00 TTL=55 ID=32907 PROTO=TCP 
> SPT=443 DPT=43579 WINDOW=351 RES=0x00 ACK PSH URGP=0 MARK=0x2
> Jul 11 11:07:57 inf-gw1 kernel: Shorewall:dropNotSyn:DROP:IN=enp9s6 OUT= 
> MAC=00:0d:88:cd:7f:c6:50:67:f0:af:f4:57:08:00 SRC=158.85.58.43 
> DST=192.168.101.2 LEN=52 TOS=0x00 PREC=0x00 TTL=49 ID=30820 DF PROTO=TCP 
> SPT=80 DPT=16779 WINDOW=514 RES=0x00 ACK RST URGP=0 MARK=0x3
> Jul 11 11:07:57 inf-gw1 kernel: Shorewall:dropNotSyn:DROP:IN=enp9s5 OUT= 
> MAC=00:0d:88:cd:7f:c5:00:13:f7:23:ef:b4:08:00 SRC=216.58.214.163 
> DST=192.168.100.2 LEN=856 TOS=0x00 PREC=0x00 TTL=55 ID=31520 PROTO=TCP 
> SPT=443 DPT=35305 WINDOW=351 RES=0x00 ACK PSH URGP=0 MARK=0x2
> 
> # shorewall version
> 5.1.5
> 
> 
> 
> # grep -v ^# /usr/share/shorewall/action.RST | grep -v ^$
> DEFAULTS DROP,-
> @1       -      -       ;;+ -p 6 --tcp-flags RST RST
> 
> #  grep -v ^# /usr/share/shorewall/action.FIN | grep -v ^$
> DEFAULTS ACCEPT,-
> @1       -      -       ;;+ -p 6 --tcp-flags ACK,FIN,PSH ACK,FIN,PSH
> 
> Functionally speaking, no user has yet reported issues accessing http or 
> https sites.
> 
> I could ignore these messages although I wasn't getting them in previous 
> systems.
> 

In shorewall.conf, remove the ":$LOG" after 'dropNotSyn' in the
BLACKLIST_DEFAULT setting.

-Tom
-- 
Tom Eastep        \   Q: What do you get when you cross a mobster with
Shoreline,         \     an international standard?
Washington, USA     \ A: Someone who makes you an offer you can't
http://shorewall.org \   understand
                      \_______________________________________________

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