Requirement of a nameserver to answer?

Requirement of a nameserver to answer?

Post by Jonathan de Boyne Pollar » Wed, 02 Jul 2003 06:31:41



IN> BTW this causes trouble with the FTP client in AIX which tries
IN> an AAAA lookup first and waits over a minute before trying an
IN> A if it doesn't get a response.

FG> If the resolver gets an "ICMP port unreacheable", it'd return
FG> an error to the FTP client, [...]

Not necessarily.  If it hasn't connect()ed the UDP socket (but is just using
sendto() instead) it may not even receive any error indication to pass along.

FG> Are you sure you get an ICMP error because of the request for
FG> AAAA record?

I can confirm his report.  DNS/UDP datagrams containing "AAAA" queries sent to
either 64.9.101.200 or 12.44.250.200 will elicit ICMP "port unreachable"
messages.