Tag :: TCP MSS ceiling

The TCP MSS clamping feature involves clamping the maximum segment size (MSS) in the TCP header of TCP SYN packets if it exceeds the configured MSS ceiling limit for the interface. Clamping MSS value helps in avoiding IP fragmentation in tunnel scenarios by ensuring that MSS is small enough to accommodate the extra overhead of GRE and tunnel outer IP headers. One of the most common use cases for this feature is connectivity towards Cloud providers via GRE which require asymmetric routing (for example DDoS protection).