Re: Access on Port 0

[Toby Speight <streapadair@gmx.net>]

0> In article <[🔎] 20021012103119.554bd308.alain@onesite.org>,
0> Alain Tesio <URL:mailto:alain@onesite.org> ("Alain") wrote:

Alain> Packets on port 0 are invalid and like packets with private
Alain> IPs or bad TCP flags, they can be used for fingerprinting the
Alain> target system.  I don't see any other reason to see a packet
Alain> on port 0.


While RFC 768 appears to reserve *source* port zero to mean "don't
reply to this datagram", I don't see any similar statement for
destination port zero.

/--------[ RFC 768 ]
| Source Port is an optional field, when meaningful, it indicates the port
| of the sending  process,  and may be assumed  to be the port  to which a
| reply should  be addressed  in the absence of any other information.  If
| not used, a value of zero is inserted.
\--------