https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873749#M913651 <P>Thanks for the help</P> Tue, 05 Apr 2016 20:24:08 GMT saleff 2016-04-05T20:24:08Z https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873747#M913642 <TABLE> <TBODY> <TR> <TD>4</TD> <TD>Apr 04 2016</TD> <TD>15:35:14</TD> <TD>419002</TD> <TD>x.x.x.x</TD> <TD>65378</TD> <TD>x.x.x.x</TD> <TD>3911</TD> <TD>Duplicate TCP SYN from inside:x.x.x.x/65378 to inside:x.x.x.x/3911 with different initial sequence number</TD> </TR> </TBODY> </TABLE> <P></P> <P>I am getting a ton of these messages. How do I stop this?</P> Fri, 21 Feb 2020 13:46:58 GMT https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873747#M913642 saleff 2020-02-21T13:46:58Z https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873748#M913647 <P>Hi,</P> <P>i think you are under an attack. Find the attackers and victims and kill them all.&nbsp;</P> <P>Just joke.</P> <P>Seriusly, you resist&nbsp;some attackers. You can shun all of them with that command shun A.B.C.D.</P> <P>You can write ACL deny all traffics from attackers.</P> <P></P> <P>Best regards.</P> Tue, 05 Apr 2016 13:58:01 GMT https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873748#M913647 aydinnmu1 2016-04-05T13:58:01Z https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873749#M913651 <P>Thanks for the help</P> Tue, 05 Apr 2016 20:24:08 GMT https://community.cisco.com/t5/network-security/asa-5500-x-duplicate-tcp-syn-from-inside/m-p/2873749#M913651 saleff 2016-04-05T20:24:08Z