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SMTP Communication Problem and Blocked

Posted on 2006-03-27
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Medium Priority
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Last Modified: 2008-02-01
Hello,

I get an error when trying to send an email to some destination email accounts. I've found the following solution on EE by Sembee but the link given doesn't work for me. Please let me know how to get around this error. Thanks.

PROBLEM
Your message did not reach some or all of the intended recipients.

      Subject:      RE:
      Sent:      3/27/2006 3:12 PM

The following recipient(s) could not be reached:

      email@comcast.net on 3/27/2006 3:12 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <server.i-mservices.local #5.5.0 smtp;550-71.111.48.108 blocked by ldap:ou=rblmx,dc=comcast,dc=net>

SOLUTION BY SEMBEE
Even getting a static IP address will not help if they are on DSL.
Most ISPs will report all of their DSL connections as dynamic. Most "static" IP addresses are just reservations in a dynamic range and you will be surrounded by dynamic IPs.

Plus if you are on DSL you will be unable to get reverse DNS configured correctly, so other people will block you on that.

The best solution for all DSL users is to use an SMTP Connector to route email via your ISP.
smtp-connector.asp" target="_blank" onclick="return openNew(this.href);">http://www.amset.info/exchange/smtp-connector.asp

======================

Please let me know how to fix this issue and/or get around it.

Thanks,
John
0
Comment
Question by:jhieb
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9 Comments
 
LVL 18

Expert Comment

by:carl_legere
ID: 16307827
sembee is amazing granted, however what is your specific symptoms?  You cannot send to some domains, what error do you get?

Are you on residental DSL/Cable, so that you beleive the ISP will block outbound email?  The recommendation to sent through your ISP's mail server is what that post is explaining.  

link appears to be up and running
0
 
LVL 1

Author Comment

by:jhieb
ID: 16307844
I posted the error in my message. I'll seperate it so it's easier to read:

Your message did not reach some or all of the intended recipients.

      Subject:     RE:
      Sent:     3/27/2006 3:12 PM

The following recipient(s) could not be reached:

      email@comcast.net on 3/27/2006 3:12 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <server.i-mservices.local #5.5.0 smtp;550-71.111.48.108 blocked by ldap:ou=rblmx,dc=comcast,dc=net>

0
 
LVL 1

Author Comment

by:jhieb
ID: 16307848
Fyi, I don't have a dedicated IP address. My ISP assigns me an IP address through DHCP and I use DSL. To get a static IP I use www.tzo.com.

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LVL 18

Expert Comment

by:carl_legere
ID: 16307947
i understand you are dynamic IP, but usually an ISP just blocks your SMTP packets wholesale, so the ISP isn't doing it.  It is comcast, who assumes that if you are in a IP block that is known to have dynamic IP setup, you are probably a roaming spammer, and they block you.

Send ALL your email through a smarthost, which will be set to the ISP's mail server (what they tell people to use if for example configuring outlook for sending email.) enter this value in the SMTP virutal server for smarthost.
0
 
LVL 1

Author Comment

by:jhieb
ID: 16312248

I don't understand what you mean. How should I send all my email through a Smart Host? I have an Exchange Server and I connect to it via Microsoft Outlook. How do I tell Exchange to connect to a Smart Host and where can I find a Smart Host?

Thanks,
John
0
 
LVL 18

Assisted Solution

by:carl_legere
carl_legere earned 1000 total points
ID: 16315065
I assume that sometime in your computer experience you have taken a comptuer, plugged it into a connection, or dialup or somesuch and configured outlook or outlook express or other mailer, and had to enter values to get mail, and how to send mail since the mailer isn't smart enough to know how to actually send mail.  This is analogous.

every ISP gives it's users a "SMTP MAIL SERVER" name or IP address they are allow to send mail through.  If you didn't have exchange and just hooked up your PC to the ISP, they would tell you stuff like: your email address is john20@bigisp.com, the pop mail server is mail.bigisp.com and the SMTP server for sending mail is smtp.bigisp.com.  Check out thier support webpages, or call them to get the correct information.

You enter this in exchange, ESM -> servers -> server name -> protocols -> SMTP-> right click default smtp virtual server -> properies -> deliery tab -> advanced -> smarthost enter the hostname or IP address of they ISP provided SMTP server here.

Exchange will no longer us it's own abilities to delivery mail, it will offload this responsability to the ISP's email server, which is now ultiamatelty responsible for delivery.

It is they best you can do given you are on a less than optimal connection for running a server.
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LVL 104

Accepted Solution

by:
Sembee earned 1000 total points
ID: 16324602
The only way to work around that message is to use an SMTP Connector.
There is no other way.

The receiving ISP is blocking connections from your IP address. While you could ask them to remove the block, they will politely tell you to go away.

Carl's answer above about putting the smart host on the SMTP VS directly, while technically correct is a bad practise to follow. It gives you no control over the message flow, means that you can use authentication if you have to, and is easily forgotten when a new server is introduced.
Use the SMTP Connector method, which resolves all of the issues with a smart host on the SMTP VS.

The link should work - it currently gets well over 400 visits a day to that one page. I will repeat it here, as the EE search system will mangle the URL.
http://www.amset.info/exchange/smtp-connector.asp

Simon.
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LVL 18

Expert Comment

by:carl_legere
ID: 16325259
Agreed
Simon do you have a second to look at this:
http://www.experts-exchange.com/Networking/Email_Groupware/Exchange_Server/Q_21794103.html
thanks
0
 
LVL 1

Author Comment

by:jhieb
ID: 16335097
Thank you both. I like both of your answers but I like the idea of creating a connector best. Thank you again.
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