Milter-greylist

robert_schmidli wrote:
>> 	/CATV/			\
>> 	/[0-9]+([^0-9])[0-9]+\1[0-9]+\1[0-9]+/	\
>> 	/[0-9]{12,}/		\
>> }
>> acl greylist list "dynamic"
> 
> Thanks.  I'll be interested to hear if you change anything.  One
> problem - I get the following error message:
> 
> bad regular expression "[0-9]+([^0-9])[0-9]+\1[0-9]+\1[0-9]+": Invalid
> back reference.
> 
> I've had to delete the offending line.

Hmm, at casual glance it should be valid.

That said, the the characters matched are really likely to be . or -, so it
seems inefficient to use back references there anyway.

Personally I'd use one of these instead:

/[0-9]{1,3}[-._][0-9]{1,3}[-._][0-9]{1,3}[-._][0-9]{1,3}[-._]/

/[0-9]+[-._][0-9]+[-._][0-9]+[-._][0-9]+[-._]/

The primary difference being the first one won't match sequences involving more
than three numbers at a time, but the second one will.
(ie: 123-123-123-1234.example.com will not match the first one, but will match
the second.)