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We've a problem similar to the question Getting a domain name off of the blacklist but the solutions posted there doesn't help.

The problem I'm facing is that our domain is probably marked automatically by recipient main server as spam.

We've a registered domain and a fixed IP. We're running Exchange 2010, with FortiGate and trial version of MS ForeFront. All was working well until recently when the ForeFront has expired, then we started getting a lot of spam mails. Then the exchange hub transport server overloaded and failed. We can't recover the server immediately, so we setup a temporary hub transport server in the DMZ while troubleshooting the failed one. During this time, our out going mail started to get bounced. Most (but not all) mails are undelivered or goes into spam box of the recipient.

We've checked numerous spam blacklist site, our IP or domain is not listed. We're currently submitting to individual mail server to have us whitelisted. This seems to happen all at the same time, which lead us to wonder if there's a general blacklist which most of our recipient server is checking from. Or there's something which we've overlooked?

The problem stills remains until today which is a week already, and we've since reinstalled the original hub transport. The temporary server is still running.

Btw, the reversed DNS of our IP doesn't match our domain name.

Any help is greatly appreciated.

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up vote 6 down vote accepted

The first problem is going to be that your r-DNS doesn't match the DNS. That's a big red-flag right there for spam engines.

If the good server is back online I'd take the temp server offline and see if the problem goes away by itself.

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This is a really good start. Also have you setup an SPF record for your domain? – polynomial Sep 14 '11 at 1:10
My colleague fix the rDNS for the MX record, now the problem is gone. Thanks – faulty Sep 14 '11 at 2:42

First step is to ensure all relevant DNS entries are correct. If you change something so that there is a DNS mismatch, as you currently have, then spend a few moments to edit the entry so that it does match. This is really important stuff.

The next step requires a bit more effort. Go to the web site for each block list you are on and follow their instructions for removal. In some cases this involves nothing more than an emailed request. For others it can involve making the request and then waiting till they have verified that you have corrected anything that might have landed you there in the first place.

Although some block lists will remove an entry after a certain amount of time in the "all clear" I suggest you don't wait for that to happen as it can result in emails to or from your users failing to reach their target in the meantime.

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The problem is the domain or IP is not listed for those we've checked. It's just bounced by the the recipient mail server. Mostly cooperates own server like us. – faulty Sep 14 '11 at 2:02

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