[H-GEN] How to block this kind of email?

[Greg Black]

On 2006-03-07, Sarah Walters wrote:

> Surely I can configure sendmail to reject mail from a server that *claims* 
> to be walters.id.au, and isn't? Please help me out here.

I'm surprised that none of the sendmail users have responded
yet, and I can't help with sendmail as I don't use it.

However, since this kind of thing is extremely common, I'm sure
there are answers.  (In my setup, I reject thousands of messages
per day with that kind of forgery, using tools that I wrote to
work with my chosen MTA.)

As always, google is your friend.  In my initial query (for
check helo sendmail), I found at least one entry[1] on the first
page of results that looks like it would provide useful clues,
especially as it comes from Neil W Rickert, who is well known as
an expert with this stuff.

Cheers, Greg

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[1] http://networking.ringofsaturn.com/Unix/sendmailtips.php