I have the following in my (Exim 2.10) configuration file:
sender_host_reject_recipients = lsearch;/usr/exim/tables/banned_sites
sender_reject = lsearch;/usr/exim/tables/banned_addresses
recipients_reject_except = postmaster@???
This has the desired effect of blocking mail from hosts that don't have
reverse-DNS entries. However, I'm experiencing problems with one particular
host. The log file contains:
1999-08-31 10:08:05 recipients from [195.147.248.109] refused (host)
1999-08-31 10:08:06 SMTP connection from [195.147.248.109]
1999-08-31 10:08:06 recipient <Anon.Emous@???> refused from
(sand.global.net.uk) [195.147.248.109] (failed to find host name from IP
address)
1999-08-31 10:08:06 SMTP connection from (sand.global.net.uk)
[195.147.248.109] closed by QUIT
Which is what I would expect. However, if I use nslookup to check the IP
address I get:
nslookup 195.147.248.109
Server: isis.uce.ac.uk
Address: 193.60.130.111
Name: sand.global.net.uk
Address: 195.147.248.109
Which, to me, inicates the presence of a reverse entry,so I then try a
forward lookup:
nslookup sand.global.net.uk
Server: isis.uce.ac.uk
Address: 193.60.130.111
Non-authoritative answer:
Name: sand.global.net.uk
Address: 194.126.82.9
If I then try exim -bh 195.147.248.109 I get:
**** SMTP testing session as if from host 195.147.248.109
**** Not for real!
>>> host in helo_verify_nets? yes
>>> looking up host name for 195.147.248.109
>>> IP address lookup failed
>>> sender_{host,net}_accept are unset
>>> host in sender_net_reject_except? no (option unset)
>>> host in sender_host_reject_except? no (option unset)
>>> host in sender_host_reject? no (option unset)
>>> host in sender_net_reject? no (option unset)
>>> looking up host name for 195.147.248.109
>>> IP address lookup failed
>>> host in sender_host_reject_recipients? yes (failed to get host name
>>> for 195.147.248.109)
LOG: recipients from [195.147.248.109] refused (host)
>>> host in rbl_except_nets? no (option unset)
>>> RBL lookup for 109.248.147.195.rbl.maps.vix.com failed
>>> => that means it's not black listed
>>> host in sender_unqualified_hosts? no
>>> host in sender_unqualified_nets? no (option unset)
>>> host in receiver_unqualified_hosts? no
>>> host in receiver_unqualified_nets? no (option unset)
>>> host in helo_accept_junk_hosts? no (option unset)
>>> host in helo_accept_junk_nets? no (option unset)
LOG: SMTP connection from [195.147.248.109]
Whereas exim -bh 194.126.82.9 produces
**** SMTP testing session as if from host 194.126.82.9
**** Not for real!
>>> host in helo_verify_nets? yes
>>> looking up host name for 194.126.82.9
>>> IP address lookup yielded sand.global.net.uk
>>> sender_{host,net}_accept are unset
>>> host in sender_net_reject_except? no (option unset)
>>> host in sender_host_reject_except? no (option unset)
>>> host in sender_host_reject? no (option unset)
>>> host in sender_net_reject? no (option unset)
>>> host in sender_host_reject_recipients? no
>>> host in sender_net_reject_recipients? no (option unset)
>>> host in rbl_except_nets? no (option unset)
>>> RBL lookup for 9.82.126.194.rbl.maps.vix.com failed
>>> => that means it's not black listed
>>> host in sender_unqualified_hosts? no
>>> host in sender_unqualified_nets? no (option unset)
>>> host in receiver_unqualified_hosts? no
>>> host in receiver_unqualified_nets? no (option unset)
>>> host in helo_accept_junk_hosts? no (option unset)
>>> host in helo_accept_junk_nets? no (option unset)
Question is, if nslookup can get sand.global.net.uk from 195.147.248.109,
why doesn't Exim, or rather, why does Exim fail the lookup? Is it because
the IP address returned by the forward lookup doesn't match the one exim
see's the connection coming from?
Paul Walsh
Senior Systems Programmer, Information Services,
University of Central England, BIRMINGHAM B42 2SU, UK
Tel: +44 (0)121 331 5708 Fax: +44 (0)121 356 2875
