[9fans] norelay option in /mail/lib/smtpd.conf

[9fans] norelay option in /mail/lib/smtpd.conf

[arisawa]

Hello,

I like upas of Plan 9.
It is simple and flexble.
Some features are added in this release to guard our system
against SPAM.

However norelay Option in /mail/lib/smtpd.conf is difficult
to understand for me:
norelay			off	#allow relaying

What is this means? The possibilities are:
1. "norelay off" means allow relaying
2. "norelay off" means disallow relaying

The comment on the right side says "allow relaying",
however there is another comment in this file:
# if norelay is on, you need to set the
# networks allowed to relay through
# as well as the domains to accept mail for

If we are allowed to write:
relay			off	# disallow relaying
it will be more clear for everyone.

By the way, smtpd can controll incomming mails
using sender-receiver address pair.
Therefore relay filter using the pair will be more powerful.

Thanks,

Kenji Arisawa
E-mail: arisawa@aichi-u.ac.jp

Re: [9fans] norelay option in /mail/lib/smtpd.conf

[bobf]

> If we are allowed to write:
> relay			off	# disallow relaying
> it will be more clear for everyone.

that's reasonable.  you can change the code in
/sys/src/cmd/upas/smtp/spam.c to reverse the
sense of the parse.

> By the way, smtpd can controll incomming mails
> using sender-receiver address pair.
> Therefore relay filter using the pair will be more powerful.

no, the sender domain is easily forged.  almost all relay
probes that we see claim to be from our domain.  the peer ip
address is more difficult to forge, so we use it.