RE: Cannot send mail to certain domains (Full Version)

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jdawg53 -> RE: Cannot send mail to certain domains (19.Aug.2004 11:19:00 PM)

I finally figured out what the problem was on our server, it was so dumb I am afraid to admit it. We are running Symantec AntiVirus 9. On the AntiVirus client, we had "Enable Interenet E-mail Auto-Protect" option selected. We installed NAV after we installed Exch 2003. I don't know if this option was selected as the default when it was installed. We did not even think of looking here, we were only looking at our NAV for Exchange.

To get the "Enable Interenet E-mail Auto-Protect" option, open the Symantec client, expand Configure and click on Internet E-mail Auto-Protect. This is where it was selected. Also click on Microsoft Exchange Auto-Protect.

I have not contacted Symantec yet to find out why this prevented email to go to certain domains (I will be doing this tomorrow) but I wanted to pass along the word. Obviously this leaves me less secure for email viruses but until I figure out that mystery, I can send emails to those domains that I couldn't in the past.

abarrote -> RE: Cannot send mail to certain domains (23.Aug.2004 10:24:00 AM)


I have Symantec Antivirus 9 installed in my Exchange Server too...
so, I came back to work today (holiday's over..) and I tried your solution: it worked on some domains but I still have the same problem with at least one domain...

So, I guess that's not the only solution...
and I can't figure out why the emails were sent before, because I installed Symantec AV9 two months ago and the Exchange Server was working fine! [Frown]

McAllyn -> RE: Cannot send mail to certain domains (25.Aug.2004 5:31:00 PM)

Will I have to stop and start services or reboot my Exchange server after I add another DNS server address?

abarrote -> RE: Cannot send mail to certain domains (25.Aug.2004 5:50:00 PM)

I don't think a reboot or service restart is necessary...

Guest -> RE: Cannot send mail to certain domains (30.Aug.2004 8:28:00 PM)

Guys had the same problem and was fixed by adding my external DNS server(s) into the SMTP Virtual Server.

Open your ˘Exchange system manager÷-> ˘Administrative groups÷->÷First Administrative group÷->÷Servers÷-˘Your Server÷->÷Protocols÷->÷SMTP÷->Right Click ˘Default Virtual Server÷->÷Properties÷->÷Delivery÷->Press ÷Advanced÷ Button->Press ˘Configure÷ Button near the ˘Configure external DNS servers÷->

Kanan -> RE: Cannot send mail to certain domains (1.Sep.2004 8:39:00 AM)

we tried the DNS change option that too did not solve the problem. What did solve the problem (should have done it right in the begining) was scanning and removing the virus, which for some reason was not detected by Symantec but got detected with Stinger.
Hope this solves the problem for some of you.

Its been an educative experince communicating with all of you

abarrote -> RE: Cannot send mail to certain domains (1.Sep.2004 2:09:00 PM)


I managed to solve the problem with the Symantec Antivirus configuration change AND adding my ISPs DNS server to the external DNS server list into the SMTP Virtual Server configuration...

McAllyn -> RE: Cannot send mail to certain domains (1.Sep.2004 10:55:00 PM)


What virus did you have? I've changed my DNS settings, and still nothing going to hotmail, msn, or aol.

Wow, second week on the job, and they are making it interesting. Apparently, this happened to them about a month and a half ago, and no one was here that could do anything about it, so they just waited for me.

McAllyn -> RE: Cannot send mail to certain domains (2.Sep.2004 3:13:00 PM)


Thanks to all of your for your help on this. I had to change the DNS(the person who set that up had it wrong anyway), then ALSO change the Internet Mail settings in Symantec.

Thanks again.

ChrisWhite85 -> RE: Cannot send mail to certain domains (13.Sep.2004 10:15:00 AM)

My problem still persists with no anti-virus or software firewall installed.

I can send to problematic domains like and ones like here in the UK.

I cant send to my customers at domains like the ones below unless i restart after sending the e-mails. They just queue up.


abarrote -> RE: Cannot send mail to certain domains (13.Sep.2004 1:00:00 PM)

hi Chris...

did you try to add your ISPs DNS server to the external DNS server list into the SMTP Virtual Server configuration?

Guest -> RE: Cannot send mail to certain domains (14.Sep.2004 11:06:00 PM)

Turning off NAV email scanning worked for me.

arielzubiri -> RE: Cannot send mail to certain domains (15.Sep.2004 10:48:00 PM)

To All Xchange Guru's;

Problems on sending emails to certain domains bug me for 2 weeks now. I've been following the resolutions I'm getting from this forum but still getting same error. " the remote connection was dropped by the remote hosts" & the sender rcvds delayed messages with mail server name & code #4.4.7 (w/c indicates problem on the rcvng end according to MS knowledge base) ..One thing I've noticed with the problematic domains was they were hosted by just one ISP. I had same problem with one domain hosted by this ISP before but after this specific domain merge with MSN everything was resolved. Never did anything on my server. Any ideas what their server was doing why they kept on dropping my servers SMTP connection?. I'm getting slow response from the ISP's tech support.

Any ideas will greatly be appreciated..


Toronto, CA

Guest -> RE: Cannot send mail to certain domains (17.Sep.2004 1:53:00 AM)

For those using Cisco PIX firewalls, you may want to turn off the MailGuard feature, which is on by default. This disallows any but core required SMTP commands, and prevents any enhanced commands such as EHLO. Unfortunately it still returns "OK" when blocking. This can cause messages to sit in a queue while the servers try to communicate with each other.

ChrisWhite85 -> RE: Cannot send mail to certain domains (17.Sep.2004 1:49:00 PM)

I get the "Connection dropped by remote host" too on troubled domains. Once there is a troubled domain stuck it stops mails going to the otherwise working domains too.

I can send to and a UK troubled domain like fine.

The domains i need to send to are other companies domains that we work for and with. Very important in our medium business environment.

When i checked the event log it tries to count the next hop to the domain and gets GetNextHop = 0ms (0 miliseconds) like it cant connect to the domain. V. Weird.

I dont use Cisco firewalls but maybe i will in a few months as we are upgrading the switches and routers.

This is a very real bug by the looks of things as there is only so much you can change in Exchange to the VS and SMTP Connector.

[ September 17, 2004, 02:01 PM: Message edited by: Chris White - Stirling ]

arielzubiri -> RE: Cannot send mail to certain domains (17.Sep.2004 9:35:00 PM)


I was also getting Event ID's 4006 (Connection Manager)on my Application Event log everytime the time limit for this email expired. When I click the link for MS help and support they don't have any articles for this event. I tried to track the message on Exchange Message Tracking Center and the message had left the organization and was transferred to receiving SMTP server. I wasn't able to track from the remote SMTP server anymore. I got Event ID 10009 (DCOM?)on my System Event Log everytime I track a message addressed to those problematic domains..don't know if this was related...

I was using Win2K3 and Exchange2K3 too.. and still getting "the remote connection was dropped by the remote hosts" error...

We're in touch with the ISP hosting the domains we're having trouble with. They were also wondering why we can send to one domain hosted on the same server as the other problematic domain. I'll post whatever reply i got from them..



ChrisWhite85 -> RE: Cannot send mail to certain domains (17.Sep.2004 10:26:00 PM)

I found my ISP to be co-operative and they sorted out that it wasn't a server problem and traced it back to Exchange so its a bug. I have to restart the server to get any of the troubled domains to send at the moment.

arielzubiri -> RE: Cannot send mail to certain domains (22.Sep.2004 3:59:00 PM)

Hello Everyone,

Never heard from the recepients ISP's tech support ti'l now. But anyways...It seems that I found the caused why we'ren't able to send to domains hosted by this particular ISP. I'm so dumbed to check all the orgs in the internet if our IPs were listed for Open RBL...this site told us that the entire IP block (1-250) provided by our ISP were blocked by two orgs..and our IPs were part of that IP block..We suspect that this might have caused the other ISP to block emails coming from us...

We did a work around..We have Unix mail servers colocated on other ISP's NOC facilities that doesn't have any issues sending out emails to other domains..We allowed our IP block to relay on that server and defined it as the Smart Hosts for our Exchange server. Hiya! this resolved our issue...I defined the smart hosts on the SMTP Mail Connector...not on the SMTP Virtual server coz it didn't work...

You can give it a try can speak to your ISP to allow you to relay on their SMTP servers and define it to be the Smart Hosts on your Exchange server...we didn't used our ISPs SMTP server coz of the Open RBL issue..we already informed them of what we've found out and waiting for their reply...

Thanks for all your help..hope this one resolves your issues too...

arielzubiri -> RE: Cannot send mail to certain domains (22.Sep.2004 4:10:00 PM)

Hello Everyone,

Forgot to say that I restarted the IIS Admin service after I defined our Unix server as our Exchange server's Smart Hosts. Other services will also be restarted when u restart this service..

Best Regards,


clandtech -> RE: Cannot send mail to certain domains (24.Sep.2004 4:30:00 AM)

Just thought I would throw in my 2 cents worth, I am on the other end of this problem, I have a 2003 server with exch 2003 and I cannot receive emails from 2 other mails servers.
I have been in contact with the admins of these domains and we have done some testing, what we have found is the mails is sent from the remote mail server but it sits on their server and will not send, I can see the connection on my server from theirs to mine in the sessions section but we do not receive the mail after a few days they get the error code 4.4.2 and a rejection notice, The SMTP connector is configured to allow all mail incoming, no firewalls, NAV 9.0 Installed, i can send and receive mail to and from anywhere else, I can do a NSlookup to these servers no worries and they can do it to me.
This has got me stuffed it just wont receive the mail, I can send to both of these domains.

Any Ideas

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