[dns-operations] ``Ya.com says "The internet is mine" ''

Rick Jones rick.jones2 at hp.com
Wed Aug 9 16:29:21 UTC 2006

Peter Dambier wrote:
> Rick Jones wrote:
>>I wonder what would happen if a helpful TCP stack, upon recieving a SYN 
>>segment destined to a port without an active LISTEN endpoint decided to 
>>complete the connection anyway to send-back some sort of helpful - "Did 
>>you really mean to connect to port <mumble>?" rather than a RST or 
>>silence?  Or better still, a UDP datagram arriving for a port without an 
>>open socket?
> ICMP does exactly that since the beginning of the internet.

Not that my analogies above were rock solid, but I don't think that an 
ICMP coming back is _quite_ the same as completing the TCP connection or 
sending a UDP datagram in response to one destined a non-listening port.

IMO, the ICMP coming back is more like the negative reply to the DNS query.

rick jones

More information about the dns-operations mailing list