On Thu, 8 Apr 2004, Iljitsch van Beijnum wrote:
You have an interesting point WRT the TTL 0. Perhaps if you receive a packet with a TTL of 0 that is destined for yourself you should just accept it?
The interesting thing is that packets with a TTL of 0 wouldn't ordinarily be seen in the wild. A router won't forward a packet with a TTL of 1 (as this becomes 0 during the forwarding process) and a host that sends out packets with a TTL 0 can only expect to communicate on the local subnet. (So I guess doing all of this with TTL 0 rather than 255 would have been just as effective.)
Even sending packets with TTL=0 is invalid, so this is a moot point. Or were you proposing modifying the sending and receiving implementations and the IPv4/6 specifications?
From hosts requirements for v4, for example:
A host MUST NOT send a datagram with a Time-to-Live (TTL) value of zero. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings