Please close this bug. It turned out that the domain mhd.se must have AAAA-records for the included 'a:' hostnames in DNS, which they didn't. And by using cloud-based e-mail they are using IPv6
without actually knowing it.
$ host f-medby.ita.mdh.se f-medby.ita.mdh.se has address 130.243.84.223
$ host -t aaaa f-medby.ita.mdh.se # first void lookup f-medby.ita.mdh.se has no AAAA record $ host -t aaaa aaaa www.netigate.se # second void lookup www.netigate.se has no AAAA record $ host -t aaaa smtp.quicknet.se # third void lookup smtp.quicknet.se has no AAAA record Many thanks to Stuart D. Gathman for pointing this out to me. -- Harald Hannelius | harald.hannelius/a\arcada.fi | +358 50 594 1020
