Paul Walsh writes ("[Exim] DNS or Exim issue?"):
> For some reason it seems that some mail from us occasionally gets bounced
> (by various Mdestinations) with the message
> unrouteable mail domain "uce.ac.uk"
I ran my DNS zone checker[1] on your domain and it said:
chiark:~> chiark-named-conf uce.ac.uk
uce.ac.uk foreign
uce.ac.uk ns1.uce.ac.uk [193.60.129.100] has 12849
uce.ac.uk www.uce.ac.uk [193.60.131.100] has 2003012901
uce.ac.uk ns1.ja.net [194.81.227.226] has 2003012901
uce.ac.uk isis.uce.ac.uk [193.60.130.111] has 2003012901
uce.ac.uk adroot.uce.ac.uk [193.60.129.189] has 12757
uce.ac.uk rootbkp.uce.ac.uk [193.60.129.182] has 12659
uce.ac.uk: warning: inconsistent serial number and/or SOA ORIGIN:
uce.ac.uk: 12757 adroot.uce.ac.uk from [193.60.129.189] adroot.uce.ac.uk, in glue from [193.60.129.100] ns1.uce.ac.uk, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
uce.ac.uk: 12659 rootbkp.uce.ac.uk from [193.60.129.182] rootbkp.uce.ac.uk, in glue from [193.60.129.100] ns1.uce.ac.uk, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
uce.ac.uk: 12849 adroot.uce.ac.uk from [193.60.129.100] ns1.uce.ac.uk, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
uce.ac.uk: 2003012901 isis.uce.ac.uk from [193.60.131.100] www.uce.ac.uk, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
uce.ac.uk: 2003012901 isis.uce.ac.uk from [194.81.227.226] ns1.ja.net, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
uce.ac.uk: 2003012901 isis.uce.ac.uk from [193.60.130.111] isis.uce.ac.uk, in glue from [193.60.131.100] www.uce.ac.uk, nameserver for uce.ac.uk
chiark-named-conf: 1 warning(s) in 1 zone(s); 0 zone(s) checked ok.
chiark:~>
(Sorry for the long lines.) So, the short answer is that your DNS is
buggered. It looks like you might have tried to change the serial
number scheme without a proper rollover.
[1] chiark-named-conf, part of chiark-utils,
ftp.chiark.greenend.org.uk:/users/ian/chiark-utils/
and in my cvsweb.
Ian.