topic Re: Check Inbound and Outbound TCP Sequece Numbers on R80.20+ in General Topics https://community.checkpoint.com/t5/General-Topics/Check-Inbound-and-Outbound-TCP-Sequece-Numbers-on-R80-20/m-p/55195#M11027 <P>The oneliner is a little&nbsp;different at R77.30.</P> Thu, 06 Jun 2019 11:32:14 GMT Ilan_Khoushy 2019-06-06T11:32:14Z Check Inbound and Outbound TCP Sequece Numbers on R80.20+ https://community.checkpoint.com/t5/General-Topics/Check-Inbound-and-Outbound-TCP-Sequece-Numbers-on-R80-20/m-p/54187#M10817 <P>Incoming and outgoing TCP sequence numbers should not be changed at the Check Point firewall. I have always asked myself how this can be explained and I have come to the following solution!</P> <P>This can be checked with the following one-liner:</P> <P>&nbsp;</P> <LI-CODE lang="markup">fw ctl zdebug + packet |grep -A 5 "==I\|==O" |grep -B 5 '&lt;IP-ADDRESS&gt;' |grep "==I\|==O\|Device"</LI-CODE> <P>&nbsp;</P> <P>Change the &lt;IP-ADDRESS&gt; in the one-liner to your device.</P> <P><BR /><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="SEQUENZ.png" style="width: 999px;"><img src="https://community.checkpoint.com/t5/image/serverpage/image-id/1306i0DA878617B19A443/image-size/large?v=v2&amp;px=999" role="button" title="SEQUENZ.png" alt="SEQUENZ.png" /></span></P> <P>Please note that "fw ctl zdebug" can cause performance problems on firewalls.</P> <P>More see here:<BR /><A href="https://community.checkpoint.com/t5/Enterprise-Appliances-and-Gaia/quot-fw-ctl-zdebug-quot-Helpful-Command-Combinations/m-p/40680/highlight/true#M3392" target="_self">"fw ctl zdebug" Helpful Command Combinations</A></P> Thu, 23 May 2019 06:54:57 GMT https://community.checkpoint.com/t5/General-Topics/Check-Inbound-and-Outbound-TCP-Sequece-Numbers-on-R80-20/m-p/54187#M10817 HeikoAnkenbrand 2019-05-23T06:54:57Z Re: Check Inbound and Outbound TCP Sequece Numbers on R80.20+ https://community.checkpoint.com/t5/General-Topics/Check-Inbound-and-Outbound-TCP-Sequece-Numbers-on-R80-20/m-p/55195#M11027 <P>The oneliner is a little&nbsp;different at R77.30.</P> Thu, 06 Jun 2019 11:32:14 GMT https://community.checkpoint.com/t5/General-Topics/Check-Inbound-and-Outbound-TCP-Sequece-Numbers-on-R80-20/m-p/55195#M11027 Ilan_Khoushy 2019-06-06T11:32:14Z