spf-discuss
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Re: domain name labels are limited to 63 characters

2004-11-26 08:44:41
In <6207(_at_)rama(_dot_)pamho(_dot_)net> "Roger Moser" 
<Roger(_dot_)Moser(_at_)rama(_dot_)pamho(_dot_)net> writes:

But the specification does not say what to do if after expanding the macros
a domain name label is longer than 63 characters. (This may happen for
example if the local-part has no dot and is 64 characters long and
<domain-spec> contains the "%{l}" macro).

I've pondered this before.  It has been my opinion that domains that
use %{l} in their SPF records can easily arrange so that valid users
don't have more than 63 characters.



If that case, should the SPF inplementation return PermFail?

I think it should be treated the same way that NXDOMAIN is treated.


Or should it truncate the label to 63 characters? If yes, on the left or on
the right side?

I don't really like this idea, but I'm not strongly opposed to it either


Or should it split the label into multi labels, that means insert dots?

The domain owner can do that by using the split characters of the
macro expansion.  For example, pobox.com uses %{l1r+}.


-wayne