550 Unroutable address (Full Version)

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Wanzenburg -> 550 Unroutable address (4.Feb.2008 11:10:11 AM)

When I send a message, after a while it return with the following error.

This is a delivery failure notification message indicating that an email you addressed to email address :
-- 'user@gigga-technology.co.za
could not be delivered. The problem appears to be :
-- Recipient email address is possibly incorrect
Additional information follows :
-- 550 Unroutable address
This condition occurred after 1 attempt(s) to deliver over a period of 0.00 hour(s).
If you sent the email to multiple recipients, you will receive one of these messages for each one which failed delivery,  otherwise they have been sent.
This enhanced system notification has been specially generated for you by Mimecast - the brain for your email.

Can anyone please assist me with the problem i'm having.

uemurad -> RE: 550 Unroutable address (4.Feb.2008 12:30:26 PM)

I responded to your previous posting, and have sent you a private message.

scionn -> RE: 550 Unroutable address (13.Mar.2008 4:52:33 AM)

I've the same problem, only when sending e-mail to one domain, can i have more information on the problem and on the resolution??


fabio.valentini -> RE: 550 Unroutable address (13.Mar.2008 7:25:46 AM)

Hi Dean, I'm suffering the same issue sending email to @mail.ru mailboxes.
Could you help me?
Thanks in advance.

scionn -> RE: 550 Unroutable address (13.Mar.2008 7:45:04 AM)

@mail.ru also for me, we have bybassed the problem using a connector for this domani only and redirecting mail via interbusiness mailserver (si sono anche io italiano).

the problem come from mail.ru server, I think that can be linked to a revers dns check that don't work well for us.
I'm investigating.

uemurad -> RE: 550 Unroutable address (13.Mar.2008 10:25:53 AM)

scionn and fabio,

The thread mentioned talked about incorrect MX records for the recipient domain.  mail.ru appears to have a proper MX record.  When you send outbound mail, do you connect directly to the recipient via DNS, or do you send to a smarthost?

fabio.valentini -> RE: 550 Unroutable address (13.Mar.2008 11:01:39 AM)

Using DNS I got the error "550 unroutable address" after the command "MAIL FROM:<username@ourdomain.com>" as reported by Exchange in the error log. Same error if I try to send a message via telnet to mxs.mail.ru 25.

Using our ISP smarthost the problem seems to be solved but I'd like to understand why we got it without smarthost. We use a static IP address but maybe the destination server is considering it dinamic as the Reverse DNS return a name that is not the "public" FQDN of our server. I'm guessing...

The main issue is that the PTR record is managed by our ISP and we cannot change it... I fear we'll be forced to use only the ISP smarthost relay.
I'm going to open a support call to our ISP in order to have more information.


Thanks in advanced for your support.

uemurad -> RE: 550 Unroutable address (13.Mar.2008 11:19:57 AM)

Many receiving systems will reject mail from IP addresses whose PTR record does not match the sending address.  It is quite possible that is the cause.  Even though your ISP manages your PTR record, you should still have a procedure for requesting DNS changes.  What does your ISP say about that?

fabio.valentini -> RE: 550 Unroutable address (13.Mar.2008 11:32:00 AM)

I'm opening a support call later today or tomorrow.
I'll post additional information when I get it.

Thanks for your help,

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