sendmail and reverse lookup

[Boex,Matthew W.]

we are having a problem with a domain sending mail to us.  we can send mail
fine to them.  i can do a forward mx lookup on their domain, rlicorp.com,
and it resolves to mail.rlicorp.com with an ip of 63.105.174.67.

if i run a dig -x 63.105.174.67 i get - 

-------------------------------------------------------------
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUERY SECTION:
;;      67.174.105.63.in-addr.arpa, type = ANY, class = IN

;; ANSWER SECTION:
67.174.105.63.in-addr.arpa.  5h41m27s IN CNAME
67.64.174.105.63.in-addr.arpa.

;; AUTHORITY SECTION:
174.105.63.in-addr.arpa.  5h41m27s IN NS  auth100.ns.uu.net.
174.105.63.in-addr.arpa.  5h41m27s IN NS  auth110.ns.uu.net.

;; ADDITIONAL SECTION:
auth100.ns.uu.net.      1d23h54m24s IN A  198.6.1.202
auth110.ns.uu.net.      32m33s IN A     198.6.1.114

;; Total query time: 4 msec
;; FROM: sch1p312 to SERVER: default -- 127.0.0.1
;; WHEN: Tue Aug 21 15:36:31 2001
;; MSG SIZE  sent: 44  rcvd: 172
-----------------------------------------------------

does this mean that auth100.ns.uu.net. and  auth110.ns.uu.net. are
authoritative for the reverse lookup.  also, when i try to use those servers
to lookup the ip, i get rejected.  could this be the reason why we are
having this problem, sendmail not being able to go out and use their
specified nameservers to do a reverse lookup?

matt