Re: [Exim] Rejecting due to reverse DNS lookup failture

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Author: michael
Date:  
To: exim-users, tje1
Subject: Re: [Exim] Rejecting due to reverse DNS lookup failture
>     At the moment we refuse to accept mail from hosts where a reverse DNS
> lookup fails to supply a hostname for the calling IP address, or if the
> returned name gives a different IP address when it is looked-up (or the
> lookup fails).


How do you do that with Exim? Is it possible to just insert a header instead,
like the RBL features can do, or just log a warning? I would first like to
get an idea how many customers are concerned. ;)

>     My question is - how common is this practice amongst members of the
> list, and how do you deal with the users who give you grief because mail
> to them is not getting through?


I check HELO for being correct, which causes similar grief. If people
complain, I send them the relevant quotes of the appropiate RFCs and
request to obey valid RFCs for staying interoperable. Depending on them
not having a clue what the heck RFCs are, I say that strict checking
avoids some spam. Everybody has a problem with spam, so they usually
accept that.

I check headers for being syntactically correct, too. And believe it or
not, it pays off in the long run. I have far fewer problems about odd
mails to debug.

> PS. When did managing a DNS zone become rocket science? Or is just a
> case of the point-and-click brigade not bothering to read Albitz & Liu?


Managing DNS, or SMTP, or POP3, or whatever else you can think of, is way
too hard for many people. The mass market brought to internet forward,
so now we have to deal with the mass market.

Michael

PS: I know, this is off-topic: ORBS could need some support.  How about
    becoming a public available secondary DNS server? Above.net should be
    shown that the majority appreciates ORBS.