Jeremy Harris wrote:
> W B Hacker wrote:
>> IIRC, the internet specifications are that <domain>.<tld> *must* be lower-case.
>
> Neither spammers nor Microsoft tend to bother about detail like that.....
>
> Hmm, I should also ask that $sender_helo_name docs be clarified in this
> regard too, I guess!
>
>> To an(y) MTA, that oridinarily applies to all characters 'to the right' of the
>> '@' symbol.
>>
>> - so - no need for an MTA to handle those as anything but lower-case, and
>> 'folding' to lower case is in order if needed.
>
> Agreed - but does exim do it for the values as presented in these variables?
>
> Cheers,
> Jeremy
>
AFAIK, yes.
Keep in mind that <domain>.<tld> are not just 'MTA' rules, they are
internet-wide, so lookup of a destination mx in a DNS could get dodgy if not
'folded'.
FWIW, a 'dig' or 'host' call to a DNS may preserve the case of the *query* with
the return, but it will have been 'folded' to lower-case to find the record.
For example, try 'dig' or 'host' for a given <domain>.<tld> in both cases and in
mixed case. Same returns.
NB: HELO strings are where UC (violations) are more prevalent. See any traffic
off NetSol & their email contractor - both of whom should know better.
HTH,
Bill
