2 ms·
Datagrams larger than the MTU can be sent, they'll just be fragmented. The point of PMTU is to avoid fragmentation where necessary, but it's still possible.
by sveiss 11y ago
Datagrams larger than the MTU can be sent, they'll just be fragmented. The point of PMTU is to avoid fragmentation where necessary, but it's still possible.
- AndyMcConachie 11y agoSometimes datagrams larger than 1500 bytes can be sent, sometimes they won't reach their destination. Fragmentation doesn't really work, and at the very least will almost always ensure out-of-order delivery. Either way you can't depend on it. PMTUD doesn't work at all on the modern Internet, not for IPv4, and not for IPv6. So again, I'm just wondering how dangerous this exploit really is. I'm not saying it isn't dangerous, I'm saying our understanding of it should be tempered somewhat due to many links not fragmenting properly that have MTUs of 1500 bytes.