Sophos XG210-HA (SFOS 17.5.8) on SG210 appliances with Sandstorm and 1x AP55 Sophos Central with Intercept X Advanced, Device Encryption, Phish Threat, Mobile Control Advanced … I think the XG sends packets to the tunnel with the false MTU . Is Path MTU available in XG .
ICMP Destination unreachable and ICMP Source Quench messages are very significant from network perspective and help keeping generic and legitimate network to operate in a proper way. Use case As an example, path MTU discovery uses ICMP Type 3, Code 4 message (ICMP Destination Unreachable – Fragmentation required and DF flag set) to update the lowest MTU in the path between source and …
IP MTU A.K.A MRU. To set the maximum transmission unit ( MTU ) size of IP packets sent on an interface. The minimum is 128 bytes; the maximum depends on the interface medium. Changing the MTU value (with the MTU interface configuration command) can affect the IP MTU value.
