Re: [Exim] "failed to find host name from IP address"

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Author: Philip Hazel
Date:  
To: Duncan Bennett
CC: exim-users
Subject: Re: [Exim] "failed to find host name from IP address"
On Thu, 21 Dec 2000, Duncan Bennett wrote:

> ------------------------------------------------------------------------------
> 2000-12-20 00:43:57 recipients from [130.246.192.49] refused (failed to
> find host name from IP address)
> ------------------------------------------------------------------------------
>
> This is confusing because reverse lookups *seem* to work:


It looks like a DNS screwup. At a quick check, it looks like some of the
nameservers have the record, and others don't. For example, this one
doesn't have it:

draco$ dig -x @chilton.rl.ac.uk. 130.246.192.49

; <<>> DiG 2.1 <<>> -x 130.246.192.49 
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 6     <<<<<<<<<<<<<<
;; flags: qr aa rd ra; Ques: 1, Ans: 0, Auth: 1, Addit: 0
;; QUESTIONS:
;;      130.246.192.49, type = ANY, class = IN


But my previous, non-specific query gave

draco$ dig -x 130.246.192.49

; <<>> DiG 2.1 <<>> -x 
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6
;; flags: qr rd ra; Ques: 1, Ans: 1, Auth: 6, Addit: 6
;; QUESTIONS:
;;      49.192.246.130.in-addr.arpa, type = ANY, class = IN


;; ANSWERS:
49.192.246.130.in-addr.arpa.    7191    PTR     jiscmail.ac.uk.


;; AUTHORITY RECORDS:
246.130.in-addr.arpa.   7191    NS      chilton.rl.ac.uk.
246.130.in-addr.arpa.   7191    NS      almond.inf.rl.ac.uk.
246.130.in-addr.arpa.   7191    NS      letterbox.rl.ac.uk.
246.130.in-addr.arpa.   7191    NS      nserv1.dl.ac.uk.
246.130.in-addr.arpa.   7191    NS      srsgsv.dl.ac.uk.
246.130.in-addr.arpa.   7191    NS      nnsa.dl.ac.uk.


However, I also see

draco$ host 130.246.192.49
130.246.192.49 PTR record not found

> Is Exim correct in its rejection? Am I doing something daft?


I think Exim is probably correct - its DNS lookup failed.

Philip


-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.