Email bouncing - conflicts b/w Exchange and POP3?

[Guest]

Hi,

I've got a strange issue occuring with one of my laptop users' Outlook.
When he sends an email from his laptop to a particular user, he'll get the
following NDR:

You do not have permission to send to this recipient. For assistance,
contact your system administrator.
<mail.[omitted].com #5.7.1 smtp;550 5.7.1 <[recipient]@[omitted].com>...
Relaying denied. IP name possibly forged [xxx.xxx.xxx.xxx]>

I can log on to his account via Citrix and email messages to this recipient
with no problems. He has a Blackberry email account which I have ported to
his laptop, via POP3. I'm wondering if this is conflicting with his exchange
acccount and the recipient's server thinks it is spam?

If that's not it, other ideas are greatly appreciated.

Thanks

Tom

 

[Guest]

Here's another data point - I don't know if it's related:

Messages that he sends to this recipient in HTML format go through.
However, plain text messages get bounced. The recipient's address in both
cases is exactly the same.

Tom

 

[Brian Tillman]

Messages that he sends to this recipient in HTML format go through.
However, plain text messages get bounced. The recipient's address in
both cases is exactly the same.

Can you post one of those bounces?

 

[Guest]

Here it is:

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

Subject: RE: [omitted]
Sent: 6/13/2005 3:51 PM

The following recipient(s) could not be reached:

[recipient omitted] on 6/13/2005 3:47 PM
You do not have permission to send to this recipient. For
assistance, contact your system administrator.
<mail.[ourserver].com #5.7.1 smtp;550 5.7.1
<[recipient]@[recipient].com>... Relaying denied. IP name possibly forged
[xx.xx.143.17]>

Thanks
Tom

 

[Brian Tillman]

Here it is:

Duh! It was in your original post, which I didn't see when I asked.

You do not have permission to send to this recipient. For
assistance, contact your system administrator.
<mail.[ourserver].com #5.7.1 smtp;550 5.7.1
<[recipient]@[recipient].com>... Relaying denied. IP name possibly
forged [xx.xx.143.17]>

This seems to indicate that the domain in your sender address does not match
the domain if the ISP through which you are sending the message. This can
happen when you don't authenticate to the outgoing server properly or you
send a message via one account but it gets delivered by the other, for some
reason.

 

[Guest]

We send mail through our Exchange server, which then goes through our ISP.
The IP indicated is for our ISP. Are you saying I need to configure his
laptop to authenticate to the ISP, or our Exchange server?

Here it is:

Duh! It was in your original post, which I didn't see when I asked.

You do not have permission to send to this recipient. For
assistance, contact your system administrator.
<mail.[ourserver].com #5.7.1 smtp;550 5.7.1
<[recipient]@[recipient].com>... Relaying denied. IP name possibly
forged [xx.xx.143.17]>

This seems to indicate that the domain in your sender address does not match
the domain if the ISP through which you are sending the message. This can
happen when you don't authenticate to the outgoing server properly or you
send a message via one account but it gets delivered by the other, for some
reason.

 

[Brian Tillman]

We send mail through our Exchange server, which then goes through our
ISP. The IP indicated is for our ISP. Are you saying I need to
configure his laptop to authenticate to the ISP, or our Exchange
server?

If you're using the Exchange server, then authentication shouldn't be
necessary.

Is your ISP hosting a domain name for you? If so, it may be presenting a
domain name that doesn't agree with the IP address it's using to send (for
example, ISP abc.com is sending the message from abc.com's IP address
1.2.3.4, but claiming to come from domain xyz.com) and the receiving mail
router perfoms a reverse lookup of the IP address, checking it agains the
apparent domain name, rejecting it if it doesn't match (i.e., the receiving
mail router sees the message coming from xyz.com at IP address 1.2.3.4,
looks the IP up, sees abc.com and decides that since abc.com doesn't match
xyz.com, it's an illegal routing).

This is speculation on my part, but some mail routers are configured to do
that. If that's the case here, only the admins of the receiving router can
fix it, if they're even inclined to do so.