https://community.cisco.com/t5/network-security/setting-out-tcp-mss-on-ftd-only-for-non-ipsec-endpoints/m-p/5234412#M1118058 <P>I found on "Firepower Management Center Device Configuration Guide", says&nbsp;for non-IPsec endpoints, you should disable the maximum TCP MSS on the Firepower Threat Defense device.<BR />If I am running IPsec tunnels on my FTD, How can we achieve disabling&nbsp;maximum TCP MSS only for&nbsp;non-IPsec endpoints?&nbsp;I know how to disable it in its entirety using flexconfig "no sysopt connection tcpmss xxxx"</P> Mon, 09 Dec 2024 14:59:09 GMT Aaron_un 2024-12-09T14:59:09Z https://community.cisco.com/t5/network-security/setting-out-tcp-mss-on-ftd-only-for-non-ipsec-endpoints/m-p/5234412#M1118058 <P>I found on "Firepower Management Center Device Configuration Guide", says&nbsp;for non-IPsec endpoints, you should disable the maximum TCP MSS on the Firepower Threat Defense device.<BR />If I am running IPsec tunnels on my FTD, How can we achieve disabling&nbsp;maximum TCP MSS only for&nbsp;non-IPsec endpoints?&nbsp;I know how to disable it in its entirety using flexconfig "no sysopt connection tcpmss xxxx"</P> Mon, 09 Dec 2024 14:59:09 GMT https://community.cisco.com/t5/network-security/setting-out-tcp-mss-on-ftd-only-for-non-ipsec-endpoints/m-p/5234412#M1118058 Aaron_un 2024-12-09T14:59:09Z