I started seeing repeated delivery failure messages from the Linux Kernel Mailing list: permalink
postfix/cleanup: 2819B22313: info: header Subject: Do You Need A Hand? from vger.kernel.org[188.8.131.52]; opendkim: too much header dataA quick Google suggested that this was because the header size was greater than the default of 65536 that OpenDKIM accepts. I tried increasing this to 262144, but this didn't help. I then set
On-Security acceptin opendkim.conf. This caused the mail to be accepted. I then had a look inside the mail:
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sego.es; s=default; <snip> $ grep DKIM-Signature msg.5SAz | wc -l 1000 $ sed -n '1,/^$/p' msg.6SAz | wc -c 396117What on earth are sego.es playing at?