Certain emails do not go through

Good afternoon to the AntiOnline community I have a question that has come up since we switch/upgraded to a new ISP and faster internet connection.

Since we have done the switch most things seem to be running faster and smoother. However I think I may have missed a step or something has gone wrong because a handful of emails are getting stuck in the exchange server and not making it to their destinations.

Most emails from in and outside the company seem to go where they should, however a few domains don't seem to recieve our emails. If you send from those domains to our company it works fine, but not vice versa. Would anyone have a suggestion why this is? I flushed the DNS on the servers just to try something, but to no avail.

One such domain that is not getting our email was aol.com. I sent an email from my aol account and it got to my work inbox just fine, but when I tried to respond it didn't make it anywhere and got stuck in the exchange queue.

Any suggestions you may have would be greatly appreciated. Do I need to check on something or perhaps I missed an important step when switching ISPs?

You mail server may be blocked by AOL....

Do you get a non deliverable message???

What is it??

Are you sending directly from your server..or uplaoding to the ISP???

Do you have a valid reverse DNS??

MLF

At first I get a msg from the exchange server saying the message has been delayed and then after a while I will get one saying the msg did not go through. It says something about SMTP dropped by the remote host or a protocol error. This was a msg in the queued up msg are of the system manager on our exchange server.

Someone also sent me a msg saying "<server.domain.LOCAL #5.5.0 smtp;521-EHLO/HELO from sender **.**.***.*** does not map to server.domain.local in DNS>" This is strange since we did change the information on the hosting company a few days ago. I can even access the outlook webaccess just fine and all emails coming in to our company get to us, but a few can't get back to the outside and get stuck...like the aol mail i sent to myself, but couldn't respond back to as it never made it out to its destination.

Does this seem strange...shouldn't it be server.domain.com? Just wondering.

We send directly from our server. Do you need more information? Let me know if I left anything out.

I think you may just have to wait it out...sometimes it takes a couple of days for new configurations to replicate around the world.

We recently had this issue...with our new website and mail server..was all resolved in about a week...

I would try again next week...if they are still blocking..you will have to contact AOL and the other domains to make them aware of your recent changes.

The domains you are sending to may need to add your domain to a white list.

Quote:

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server.domain.LOCAL #5.5.0 smtp;521-EHLO/HELO from sender **.**.***.*** does not map to server.domain.local in DNS

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From this error looks like they havent received the DNS change of you mail server yet...

MLF

That is what I am hoping that it is simply time to play the waiting game. It is annoying though since aol is not the only place that isn't getting our email.

Is it supposed to say server.domain.local? or is it supposed to say something else...someone was telling me that they thought it should give a msg of server.domain.com. Not sure they know what they are talking about, but it made me think.

Is there anything else I should double check on my server or firewall? Perhaps change a DNS or something? Or restart services? just wondering if I can do anything to make sure its not something on our side.

Thanks for the info Morganlefay.

AOL is actually the worst...it always seems to that them the longest :rolleyes:

the sever.domain.local issue I beleive is depending on where you are getting your error from...your server or thiers

MLF

So it is possible it is something on our end?

The only strange thing is that the majority (nearly all) emails are going through except to a few like comcast, aol, etc. Which leads me to believe they have outdated records or something of that sort. Perhaps I should give them a call?

When switching from one ISP to another do I need to make any changes on my servers? A DNS change or check on anything that might be specific to the old ISP?

Any chance that I need to change the DNS forwarders?

In the exchange system manager queue I get msgs such as...

"An SMTP protocol error occured"
"The connection was dropped by the remote host"
"The connection was dropped due to an SMTP protocol event sink"

These msgs come from emails that aren't making it through and keep trying to send over and over.

Well...this all depends on your set up??

Have you contacted your registrar and ISP on the changes to the mail server and confirmed your MX records have been changed??? and your settings are correct???

I am assuming this is Exchange 2003???

MLF

Everything seems to check out all records are correct and the people who host our domain for our webmail and website are fine. The DNS on SMTP server seem to be correct.

We use excahange 2003

Things keep bouncing/not making it to their destination. However, when I send email from a domain like aol to my work email it makes it just fine. The other way from my work email to aol does not.

Anyone ever have this type of issue? I have found some articles on possible DNS problems (which I don't see us having any) and Anti-Virus/Spam issues which I am emailing the Sybari people now to see if have any known issues when you switch ISPs.

So after doing some digging around I found that our new ISP did not have a PTR (reverse DNS) listed for our domain. I have had them add it and they told me it should be in full effect in about 24 hours.

I think this could be it, but I'll have to wait and see I guess.

Yes...alot of mailservers will verify that the domain resolves to the IP before accepting mail....if it doesnt...it will bounce.

MLF

From your exchange server use telnet to connect to port 25 one of the email servers that is not accepting mail. Try and send an email, when it fails note the response. Paste the response into google, this will confirm if dns is the problem.

It does not sound like mail is being blocked by an anti spam solutions but you can verify here www.dnsstuff.com Go to ip tests, spam database lookup and enter your exchange servers external IP address.

Best of luck!

MISSION ACCOMPLISHED.

As soon as our new ISP completed adding the PTR entry and gave it a few hours to propagate everything starting moving through smoothly. No emails are left in the queue.

Your help was very much appreciated. A special thanks to Morganlefay.

Glad to hear its all sorted out..

we changed ISP, webhosting nd mailservers recently... it took about a week all in all for the dns to replicate throughout for everything.

Just because our records were updated....didnt mean everyone elses were

I likes special thanks.... ;)

MLF