I have recieved a number of complaints about people not being able to send
mail to my system; in particular from mail.zoo.co.uk. I have sender
verification turned on:
sender_verify = true
sender_verify_except_nets = \
131.111.0.0/255.255.0.0:200.9.147.0/255.255.255.0:192.153.153.0/255.255.255.0
(the \ isn't there in reality; it's all one line)
This site is getting the 451 temporarily unable to verify sender message.
I tried doing a DNS lookup on this site, and got something odd:
16:40 mole:~> nslookup mail.zoo.co.uk
Server: mole.bio.cam.ac.uk
Address: 131.111.36.9
Non-authoritative answer:
Name: mail.zoo.co.uk
Address: 194.216.59.4
produced almost instantly. However:
16:43 mole:~> nslookup -querytype=mx mail.zoo.co.uk
Server: mole.bio.cam.ac.uk
Address: 131.111.36.9
*** mole.bio.cam.ac.uk can't find mail.zoo.co.uk: Server failed
which took a long time to appear (some sort of time out, I suppose). I'm
not much of a DNS expert, so:
a) Could this be responsible for the error message that exim is
generating and if so,
b) Whose fault is it likely to be?
Thanks in advance.
Tim.
--
--------------------------------------------------------------------------
Dr T J R Cutts Tel: +44 1223 333596
Dept. of Biochemistry, 80 Tennis Court Rd., Fax: +44 1223 766002
Cambridge, CB2 1GA, UK
--
*** Exim information can be found at
http://www.exim.org/ ***
