I was just thinking about this fix I introduced, and while it does work
against blank lines, it does not work against lines that contain only
control characters. Anyone got any better ideas?
Besides, If someone was good enough to have installed the *check* mail
hooks on the initial relay host, we would have a semblance of the original
sender in the headers (a semblance to recognize a possible IP spoofing)
<><Randall Grimshaw, Network Programmer, Syracuse University, 315-443-5779
On Mon, 9 Mar 1998, Randy Grimshaw wrote:
> You can add the following rule to the *check_mail* hook in sendmail
> R$*<> $#error $@ 5.7.1 $: "551 You must provide a proper from address"
> This will require the sender to provide something as a mail from: value
> and then any content given will be checked by the regular tests that you
> provide. See sendmail.org for additional info about the hook.
> <><Randall Grimshaw, Network Programmer, Syracuse University, 315-443-5779
> On Fri, 6 Mar 1998, Chris Brenton wrote:
> > The blank return path bothered me. I've tested this off of a few mail systems
> > and was surprised to see that all of them would accept a blank "mail from:"
> > line. Are there any firewalls out there that would kick this message out by
> > default? Mail systems?