Re: [9fans] small smtpd bug

Re: [9fans] small smtpd bug

[bobf]

> I know verifying the sender domain is a fairly weak test (you need only supply
> a valid one), but it doesn't work unless you are operating a filrewall configuration.
>
> See the following in /sys/src/cmd/upas/smtp/rmtdns.c
>
> 	fd = open("/net.alt/dns", ORDWR);	/* look up all others */
> 	if(fd < 0)				/* dns screw up - can't check */
> 		return 0;
>
>
> This would do as a quick patch....
>
> 	fd = open("/net.alt/dns", ORDWR);	/* look up all others */
> 	if (fd < 0)
> 		fd = open("/net/dns", ORDWR);
> 	if(fd < 0)				/* dns screw up - can't check */
> 		return 0;
>
> This is slightly at odds with what mxdial does. Perhaps a command line
> option to smtpd to tell it which dns to use?

this patch doesn't work well for us because of pathologies of our
internal domain structure.  i will probably change it to look in
/net by default, but to override that with the network specified with
the '-n' command line argument.  this assumes that the
peer and the appropriate DNS are on the same network, but that
assumption does not seem unreasonable.

[9fans] small smtpd bug

[nigel]

I know verifying the sender domain is a fairly weak test (you need only supply
a valid one), but it doesn't work unless you are operating a filrewall configuration.

See the following in /sys/src/cmd/upas/smtp/rmtdns.c

	fd = open("/net.alt/dns", ORDWR);	/* look up all others */
	if(fd < 0)				/* dns screw up - can't check */
		return 0;


This would do as a quick patch....

	fd = open("/net.alt/dns", ORDWR);	/* look up all others */
	if (fd < 0)
		fd = open("/net/dns", ORDWR);
	if(fd < 0)				/* dns screw up - can't check */
		return 0;

This is slightly at odds with what mxdial does. Perhaps a command line
option to smtpd to tell it which dns to use?