Please help with DNSBL setup

[Bill Horne]

Thanks for reading this.

I'm setting up DNS-based Blackhole list lookups for my sendmail MTA,
and I'd appreciate help. This is not a sendmail question as yet: I'd
like to solve a problem with 'dig' before starting sendmail tests.

First, I try to get a response from the ordb dns, but 
when I do a command like:

dig @relays.ordb.org 2.0.0.127.relays.ordb.org any

I get a response that says 
"connection timed out; no servers could be reached".

When I log all packets, I'm seeing this sequence:

Oct 29 15:41:10 billhorne kernel: IN= OUT=eth0 \
SRC=65.96.15.133 DST=63.240.76.19 LEN=61 TOS=0x00 PREC=0x00 \
TTL=64 ID=5003 DF PROTO=UDP SPT=1088 DPT=53 LEN=41 

Oct 29 15:41:10 billhorne kernel: IN=eth0 OUT= \
MAC=00:20:af:30:da:9d:00:0b:5f:ee:aa:a8:08:00 \
SRC=63.240.76.19 DST=65.96.15.133 LEN=272 TOS=0x00 PREC=0x00 \
TTL=240 ID=55038 DF PROTO=UDP SPT=53 DPT=1088 LEN=252 

Oct 29 15:41:10 billhorne kernel: IN= OUT=eth0 \
SRC=65.96.15.133 DST=62.242.0.190 LEN=74 TOS=0x00 PREC=0x00 \
TTL=64 ID=0 DF PROTO=UDP SPT=1088 DPT=53 LEN=54 

Oct 29 15:41:11 billhorne kernel: IN=eth0 OUT= \
MAC=00:20:af:30:da:9d:00:0b:5f:ee:aa:a8:08:00 \
SRC=62.242.0.190 DST=65.96.15.133 LEN=56 TOS=0x00 PREC=0x00 \
TTL=40 ID=37948 DF PROTO=ICMP TYPE=3 CODE=3 \
[SRC=65.96.15.133 DST=62.242.0.190 LEN=74 TOS=0x00 PREC=0x00 \
TTL=43 ID=0 DF PROTO=UDP SPT=1088 DPT=53 LEN=54 ] 

Oct 29 15:41:15 billhorne kernel: IN= OUT=eth0 \
SRC=65.96.15.133 DST=62.242.0.190 LEN=74 TOS=0x00 PREC=0x00 \
TTL=64 ID=0 DF PROTO=UDP SPT=1088 DPT=53 LEN=54 

Oct 29 15:41:15 billhorne kernel: IN=eth0 OUT= \
MAC=00:20:af:30:da:9d:00:0b:5f:ee:aa:a8:08:00 \
SRC=62.242.0.190 DST=65.96.15.133 LEN=56 TOS=0x00 PREC=0x00 \
TTL=40 ID=38535 DF PROTO=ICMP TYPE=3 CODE=3 \
[SRC=65.96.15.133 DST=62.242.0.190 LEN=74 TOS=0x00 PREC=0x00 \
TTL=43 ID=0 DF PROTO=UDP SPT=1088 DPT=53 LEN=54 ] 

So my questions: why am I receiving ICMP type 3, code 3 respones?  If
I understand the docs, it's a "Port Unreachable" response, yet I don't
see any mention of a special port number for DNS queries in the ordb.org 
FAQ. I can ping relays.ordb.org OK, and their web site is online.

TIA.

Bill Horne