551 5.7.1 Unable to Resolve IP Address

[Alan]

I have an Exchange 2003 server and just starting today I am not able to send
e-mail to a specific address. When I try i get the following message: 551
5.7.1 Unable to Resolve IP Address.

I can send to the address from my home e-mail account.
This was working without issue in the past.

Any ideas?

[Leif Pedersen [MVP]]

Hi,

Make sure that you have a PTR record in the public DNS for your exchange
server.

Leif

Post by Alan
I have an Exchange 2003 server and just starting today I am not able to send
e-mail to a specific address. When I try i get the following message: 551
5.7.1 Unable to Resolve IP Address.
I can send to the address from my home e-mail account.
This was working without issue in the past.
Any ideas?

[Juan Perez]

Hi

i have a problem like that, some domanins dont accept my emails.
I have a PTR record, and im not in any blacklist but the smtp queue its
full of resend connectors.
I have two mx entries mail.xxxx and mail2.xxxx, the firts one of an isp
and the other to my local exchange. In the error messages never shows
nothing about mail2 " <mail.xxx #5.5.0 smtp;550 not local host ". Im
not using smarthost... . Where do i link my exchange to mail2.xxx?
could be that?

tx all

[Alan]

Update: I didn't make any changes and the e-mails started being delivered to
the address they were failing the very next day. I guess it was something
out in the cloud.

Post by Juan Perez
Hi
i have a problem like that, some domanins dont accept my emails.
I have a PTR record, and im not in any blacklist but the smtp queue its
full of resend connectors.
I have two mx entries mail.xxxx and mail2.xxxx, the firts one of an isp
and the other to my local exchange. In the error messages never shows
nothing about mail2 " <mail.xxx #5.5.0 smtp;550 not local host ". Im
not using smarthost... . Where do i link my exchange to mail2.xxx?
could be that?
tx all

[jesmin ningthoujam]

Well, make sure to get your ISP create a Reverse NDR PTR for your mail domain.
Most of the major ISP's mail server will not accept mails...

The issue seems to be resolved at this point but will be very intermittent. The Error might occur again at some point of time in the near future ..

:)
--
jesmin ningthoujam

"Alan" <***@discussions.microsoft.com> wrote in message news:EF2FF353-6139-423A-A5DC-***@microsoft.com...
I have an Exchange 2003 server and just starting today I am not able to send
e-mail to a specific address. When I try i get the following message: 551
5.7.1 Unable to Resolve IP Address.

I can send to the address from my home e-mail account.
This was working without issue in the past.

Any ideas?