🚀 go-pugleaf

> On 18 Dec 90 14:22:13 GMT, lws@comm.wang.com (Lyle Seaman) said:
> lws> It's worth noting that the world is still pretty split about how to
> lws> handle the % hack, with some sites giving it precedence over ! and
> lws> others not.  This is an unfortunate situation.  The only solution
> lws> is to avoid mixing % and !  if at all possible.

pcg@cs.aber.ac.uk (Piercarlo Grandi) writes:
> Oh again. % should *never* be expanded by other than the target machine
> of a mail exchange.
>
> Example: a!b!c%d.e.f
>     on a UUCP machine: route this to the 'b' site which is a
>     neighbour of the 'a' site, and on 'b' deliver mail to
>     'c%d.e.f'.

This is excellent advice, and I agree with it 100%, but bear in mind that
it contradicts RFC1123, which says that the example should be passed to
d.e.f by whatever means, and d.e.f should decide what to do with a!b!c.
(Basically the recommendation is that ! binds tighter than %).

Many machines (including UUNET) disobey RFC1123 in this respect, and get
mail delivered.  Many other machines comply with RFC1123, and generally
lose mail from UUCP sites that has %'s in the destination address.

I'd agree that addresses with both !'s and %'s should be avoided whenever
possible, but UUCP sites can't avoid ! addresses, and lots of mail gateways
rewrite "From:" addresses into a % form.

---
Tom Fitzgerald   Wang Labs        fitz@wang.com
1-508-967-5278   Lowell MA, USA   ...!uunet!wang!fitz