3 ms·
Is it permissible to set DF on a datagram which is already fragmented? Or if not formally impermissible, does it trigger some interesting bugs in something that
by zrm 3y ago
Is it permissible to set DF on a datagram which is already fragmented? Or if not formally impermissible, does it trigger some interesting bugs in something that assumes DF set = not fragmented?
- LegionMammal978 3y agoThe IPv4 RFC doesn't have anything precluding DF on a fragment. Since each fragment is a datagram in its own right, adding a DF just means that it can't be fragmented even further. The example fragmentation algorithm only considers DF on a per-datagram basis, regardless of whether or not it is a fragment of some original datagram. (It does take care to forward the original offsets and MF flag correctly, to account for the datagram being a fragment.)