[exim] RDNS lookup failures...

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Author: James Price
Date:  
To: exim-users
Subject: [exim] RDNS lookup failures...
I want to confirm what I need to deny email if there is no PTR record on a
connecting IP. I do NOT want to lookup the reverse (PTR) and then look at
the A record also and then fail.

I am seeing some errors in my logs to hosts that do have PTR records.

My RDNS related parts of my config:
Main section:
host_lookup = *

acl_check_rcpt:
# No reverse DNS means no accept
deny    message       = X-Broken-Reverse-DNS: no host name for IP address
$sender_host_address
!verify        = reverse_host_lookup


Here are some logs...

exim_mainlog:2007-03-05 13:10:28 H=(MHRMAIL.MILL-USA.COM) [4.71.42.67]
F=<scrotty@???> rejected RCPT <rick@???>: host lookup
failed (4.71.42.67 does not match any IP address for mhrmail.mill-usa.com)

When I do a lookup manually:
border1# host 4.71.42.67
67.42.71.4.in-addr.arpa domain name pointer MHRMAIL.MILL-USA.COM.

Granted its in CAPS, but there is a ptr record.

Now in another instance:
exim_mainlog:2007-03-07 14:58:10 H=(DC07CLFPN2.CITYOFCHICAGO.ORG)
[216.125.147.3] F=<mberkshire@???> rejected RCPT
<monica@???>: host lookup failed (216.125.147.3 does not match
any IP address for 216.125.147.3.cityofchicago.org)

Manual lookup:
border1# host 216.125.147.3
3.147.125.216.in-addr.arpa domain name pointer
216.125.147.3.cityofchicago.org.

It resolves just fine.

I'm guessing what is happening is because I collect the hostname in the main
section of the config, its causing a forward and reverse lookup which don't
match and then bounce. I'm also guessing I just need to remove the
host_lookup = * and keep the deny in my acl_check_rcpt.

If anyone can clarify this for me it would be great. I'm an old Qmail
person and am quite new to Exim.

Thanks,
James

James R. Price
Digital Chicago Networks, Inc.
3636 S. Iron St., Chicago, IL 60609
Tel/Fax/Cell: 800-603-0769
Web: www.digitalchicago.net
Email: james@???