The co-oporate customer is looking to rectify their mail system but I have found
it very difficult to convince 3 ISP's that it is something in the set-up of
their email system. This particular ISP has been very uncooperative in the past
so I don't expect any phone call from them. Oh well, I tried.
Mike Kovacich
System Administrator
Inter-PC Internet Services
David Payer wrote:
> Can you recommend a good spam filtering software which accepts
> incoming email and then filters it based on certain criteria (at the server
> level) before the mail is delivered to the user's mailbox.
> *************
> I know that Symantec has a solution.
>
> But let me make an appeal to NT ISPs. I have recently gone through a
> couple situations where customers cant send their mail from their corporate
> headquarters to their mailbox with us because we have REVERSE LOOKUP
> REQUIRED turned on at the server level.
>
> I have run into several ISPs who have not heard of this and they
> treat me as if I am proposing some new standard of things. I don't believe I
> am. You do all create inverse addressing tables when you do your DNS don/t
> you? When mail servers connect, they say "HELO Im so and so" you should
> then be able to have your system do an inverse lookup (in-addr-arpa) and
> determine if that is actualy who is says it is. If it isn't, why bother
> receiving from them?
> I went through the logs recently after weeks of having my mail
> server reject connections that didn't have inverse addressing setup. 95% of
> the rejections were to IP addresses that I could not telnet into port 25 on,
> indicating they were not SMTP servers or they were from temporary IPs.
>
> If all ISPs required that mail servers only connect if the other
> side is *WHO THEY SAY THEY ARE* we would cut down on 90% of the spam. If
> anyone can put up a machine on a network and just start spitting out email,
> how will we ever stop SPAM?
>
> I think it is important to police ourselves so the government (or an
> affiliate like the post office) doesn't come in and say: There are problems
> with unsolicited mail, *we* have the solution for you and the monthly tax
> for it will be $.XXX.
> Please have your mail servers properly addressed. With NT's DNS
> Manager it is easy to do by simply affirming the default check mark at the
> prompt (BUT when you use ADD HOST, the default is OFF).
>
> One of my machines got put on a realtime blackhole list for a bit
> because I had turned this off (plus they found a way to overcome my ban on
> relaying). I do NOT want to go out of business because some spammers
> hijacked my mail server and AOL decides to blacklist me. Friends, I see this
> as a real possibility.
>
> David Payer
> OMNI Internet
> www.iowalink.com
>
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