Problems with Port 25 & Exchange

Problems with Port 25 & Exchange

Post by nphill.. » Thu, 07 Jan 1999 04:00:00



I have a problem connecting my Exchange server to my ISP. My ISP can
now connect to my Exchange Server but it takes quite some time for
them to see my Port 25. If I telnet to the Exchange Server internally
it takes about 50 seconds for a response (which im told is far
excessive, internally it should be near instantaneous). Also I cannot
send extenal E-Mails, internal ok. All I get is the following:

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

      Subject:  test
      Sent:     06/01/99 14:51

The following recipient(s) could not be reached:


            No transport provider was available for delivery to this
recipient.

My questions are:
What reasons are there for a slow response from port 25, any settings
needed under control panel (NT4) TCP/IP, DNS etc.

Why can I not send external E-Mails, I can recieve external E-Mails.

Any help would be appreciated.

Thanks,

nick


 
 
 

Problems with Port 25 & Exchange

Post by Andy Web » Thu, 07 Jan 1999 04:00:00


The slow response is most likely due to missing reverse lookup records in
DNS.

Andy


>I have a problem connecting my Exchange server to my ISP. My ISP can
>now connect to my Exchange Server but it takes quite some time for
>them to see my Port 25. If I telnet to the Exchange Server internally
>it takes about 50 seconds for a response (which im told is far
>excessive, internally it should be near instantaneous). Also I cannot
>send extenal E-Mails, internal ok. All I get is the following:

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

>      Subject: test
>      Sent: 06/01/99 14:51

>The following recipient(s) could not be reached:


>            No transport provider was available for delivery to this
>recipient.

>My questions are:
>What reasons are there for a slow response from port 25, any settings
>needed under control panel (NT4) TCP/IP, DNS etc.

>Why can I not send external E-Mails, I can recieve external E-Mails.

>Any help would be appreciated.

>Thanks,

>nick




 
 
 

Problems with Port 25 & Exchange

Post by Rich Matheis » Fri, 08 Jan 1999 04:00:00


                                        [ snip ]

Quote:>My questions are:
>What reasons are there for a slow response from port 25, any settings
>needed under control panel (NT4) TCP/IP, DNS etc.

The slowness is most likely caused by the absence of the appropriate
PTR records in your DNS database. Exchange is trying to resolve your
clients IP address to a hostname. The best fix is to correct the DNS.
The next-best fix is to disable reverse resolution:

 HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIMC\Parameters

 Value name:    DisableReverseResolve
 Value type:    REG_DWORD
 Value:                 0x0 (don't disable it)
                        0x1 (disable it)

Then stop and restart the IMS.

Quote:>Why can I not send external E-Mails, I can recieve external E-Mails.

This problem has many causes. Here's a list (maybe not complete, but
enough to get you started) of MS KB articles describing various causes
and their solutions:

Q155430 "XCLN: ErrMsg: No Transport Provider was Available for
Delivery"
Q166163 "XCLN: Err Msg: No Transport Provider Was Available"
Q170694 "OL97: Unable to Send Mail Using the CompuServe Mail Service"
Q176731 "OL97: ErrMsg: No Transport Provider was Available"
Q180484 "OL98: ErrMsg No Transport Provider was Available"
Q188979 "XADM: NDR When Sending to Recipient From Offline Address
Book"
Q192349 "XADM: Messages NDR after Applying 5.5 Service Pack or 5.0
Hotfix"
Q192533 "XCLN: MAPI Spooler Sends NDRs During Folder Synchronization"

----------------------------------------------------------------
Richard Matheisen                           Wang Laboratories
Microsoft Certified System Engineer         Tewksbury, MA USA