IIS and SMTP - Unable to send from localhost

Author

Unable to send from localhost

Toby Herring

2004-07-25, 8:54 pm

I have a multihomed colo server (Windows 2003 Standard) that's hosting
mail, web, and some other services. 5 domain names are associated with
this server.

4 domains receive mail on one IP address using an e-mail proxy
(http://www.sssolutions.net/ew/) and a 3rd-party mail server (not
relevant.)

The other domain receives mail on a second IP address via Microsoft
SMTP.

The problem is that both of these servers monitor specific IP addresses
for mail. Neither of them monitors the loopback address. I can't set
up the proxy to pick up the loopback address. (Well, actually, I can,
but the proxy communicates with the 3rd party mail server on the
loopback address. I can't set the loopback address as trusted in the
mail server, because that would make the server an open relay due to the
mail proxy. I don't want to have to authenticate to send mail, and the
From: address on some of these emails will be in the domain covered by
the MS SMTP server.)

I've tried setting the MSSMTP instance to monitor all unassigned
addresses, which makes it respond on the loopback, but when I try to
send mail from it, I get the following error:
"Message delivery to the remote domain 'grimware.com' failed for the
following reason: Unable to deliver the message because the destination
address was misconfigured as a mail loop."

I've also tried setting up a separate instance of MSSMTP to monitor all
unassigned, but it fails with the same message.

I'm at my wit's end. I've tried MSDN, MSKB, and Google searches galore.
I've searched all MS newsgroups through Google, also. No luck so far,
although I've tried things I've found in a couple of these resources
with no luck.

Any hope, or do I have to go with authentication and/or use a relay off
my box?

--
Toby Herring
MCDBA, MCSD, MCP+SB

Ken Schaefer

2004-07-26, 2:56 am

You say you have two IP addresses? And MS SMTP server listens on one of
those addresses?

Then allow the second IP address to relay (but not the first IP address).
You may also want to add 127.0.0.1 in the "allowed to relay" dialogue box.
This should allow the MS SMTP server to relay mail from hosts in the "Allows
to relay mail" dialogue.
-or-
Use a component that drops a text file directly into the /pickup directory
of the MS SMTP server. Any file that is dropped into that folder is send
regardless of relay restrictions.

Cheers
Ken

"Toby Herring" <devnull*@*nospam.spam> wrote in message
news:%23TvzgSqcEHA.2520@TK2MSFTNGP12.phx.gbl...
> I have a multihomed colo server (Windows 2003 Standard) that's hosting
> mail, web, and some other services. 5 domain names are associated with
> this server.
>
> 4 domains receive mail on one IP address using an e-mail proxy
> (http://www.sssolutions.net/ew/) and a 3rd-party mail server (not
> relevant.)
>
> The other domain receives mail on a second IP address via Microsoft
> SMTP.
>
> The problem is that both of these servers monitor specific IP addresses
> for mail. Neither of them monitors the loopback address. I can't set
> up the proxy to pick up the loopback address. (Well, actually, I can,
> but the proxy communicates with the 3rd party mail server on the
> loopback address. I can't set the loopback address as trusted in the
> mail server, because that would make the server an open relay due to the
> mail proxy. I don't want to have to authenticate to send mail, and the
> From: address on some of these emails will be in the domain covered by
> the MS SMTP server.)
>
> I've tried setting the MSSMTP instance to monitor all unassigned
> addresses, which makes it respond on the loopback, but when I try to
> send mail from it, I get the following error:
> "Message delivery to the remote domain 'grimware.com' failed for the
> following reason: Unable to deliver the message because the destination
> address was misconfigured as a mail loop."
>
> I've also tried setting up a separate instance of MSSMTP to monitor all
> unassigned, but it fails with the same message.
>
> I'm at my wit's end. I've tried MSDN, MSKB, and Google searches galore.
> I've searched all MS newsgroups through Google, also. No luck so far,
> although I've tried things I've found in a couple of these resources
> with no luck.
>
> Any hope, or do I have to go with authentication and/or use a relay off
> my box?
>
> --
> Toby Herring
> MCDBA, MCSD, MCP+SB
>
>
>

Toby Herring

2004-07-26, 5:57 pm

The MSSMTP service was set up to allow relay from 127.0.0.1. Relaying
wasn't the problem. It's this "misconfigured as a mail loop" thing that I
can't seem to get around.

The MSSMTP service isn't even able to send out administrative warning
e-mails, they end up in the badmail directory, too.

Any other ideas?

--
Toby Herring
MCDBA, MCSD, MCP+SB

"Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
news:O0SY%23lscEHA.3420@TK2MSFTNGP12.phx.gbl...
> You say you have two IP addresses? And MS SMTP server listens on one of
> those addresses?
>
> Then allow the second IP address to relay (but not the first IP address).
> You may also want to add 127.0.0.1 in the "allowed to relay" dialogue box.
> This should allow the MS SMTP server to relay mail from hosts in the
"Allows
> to relay mail" dialogue.
> -or-
> Use a component that drops a text file directly into the /pickup directory
> of the MS SMTP server. Any file that is dropped into that folder is send
> regardless of relay restrictions.
>
> Cheers
> Ken
>
> "Toby Herring" <devnull*@*nospam.spam> wrote in message
> news:%23TvzgSqcEHA.2520@TK2MSFTNGP12.phx.gbl...
>
>

Ken Schaefer

2004-07-26, 8:54 pm

Have you checked DNS resolution?

Cheers
Ken

"Toby Herring" <therring*@*teletrack.com> wrote in message
news:e22LlRzcEHA.2352@TK2MSFTNGP09.phx.gbl...
> The MSSMTP service was set up to allow relay from 127.0.0.1. Relaying
> wasn't the problem. It's this "misconfigured as a mail loop" thing that I
> can't seem to get around.
>
> The MSSMTP service isn't even able to send out administrative warning
> e-mails, they end up in the badmail directory, too.
>
> Any other ideas?
>
> --
> Toby Herring
> MCDBA, MCSD, MCP+SB
>
>
> "Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
> news:O0SY%23lscEHA.3420@TK2MSFTNGP12.phx.gbl...
address).[vbcol=seagreen]
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> "Allows
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>

Toby Herring

2004-07-27, 8:01 am

The other mail server works fine for outbound mail. I can browse the web.
I can use NSLookup to dig up DNS info all day long.

And I'm assuming that if the DNS were the problem, the message I'd be
getting would be something along the lines of unable to find/connect to
host.

Does anyone know what this "misconfigured as a mail loop" message actually
means? Deciphering the error message would go a long way towards resolving
this thing.

--
Toby Herring
MCDBA, MCSD, MCP+SB

"Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
news:OA5Rx63cEHA.3096@tk2msftngp13.phx.gbl...
> Have you checked DNS resolution?
>
> Cheers
> Ken
>
> "Toby Herring" <therring*@*teletrack.com> wrote in message
> news:e22LlRzcEHA.2352@TK2MSFTNGP09.phx.gbl...
I[vbcol=seagreen]
of[vbcol=seagreen]
> address).
> box.
> directory
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> with
> addresses
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>
>

Jeff Cochran

2004-07-27, 5:57 pm

On Tue, 27 Jul 2004 09:07:22 -0400, "Toby Herring"
<therring*@*teletrack.com> wrote:

>The other mail server works fine for outbound mail. I can browse the web.
>I can use NSLookup to dig up DNS info all day long.
>
>And I'm assuming that if the DNS were the problem, the message I'd be
>getting would be something along the lines of unable to find/connect to
>host.
>
>Does anyone know what this "misconfigured as a mail loop" message actually
>means? Deciphering the error message would go a long way towards resolving
>this thing.

Misconfigured as mail loop means the system is configured to foirward
to itself from itself, meaning it will continuously send email through
itself to itself to be delivered by itself, ad nauseum. Using your
own IP as a smart host can generate this, though there should be an
entry in the log to match this condition.

Jeff

Ken Schaefer

2004-07-27, 8:55 pm

"Jeff Cochran" <jeff.nospam@zina.com> wrote in message
news:4106c5dd.556806495@msnews.microsoft.com...
> On Tue, 27 Jul 2004 09:07:22 -0400, "Toby Herring"
> <therring*@*teletrack.com> wrote:
>
web.[vbcol=seagreen]
actually[vbcol=seagreen]
resolving[vbcol=seagreen]
>
> Misconfigured as mail loop means the system is configured to foirward
> to itself from itself, meaning it will continuously send email through
> itself to itself to be delivered by itself, ad nauseum. Using your
> own IP as a smart host can generate this, though there should be an
> entry in the log to match this condition.

Or, some weird DNS resolution problem where the SMTP server thinks that mail
for all domains (or the domain in question) should be delivered to 127.0.0.1
(or whatever IP address is is using)

Cheers
Ken

Toby Herring

2004-07-28, 7:57 am

That's most likely what the problem is, then. The MSSMTP server isn't
configurable enough for me to specifically tell it to watch localhost, but
no other addresses, and it isn't smart enough to realize that even though
the target mail server is on the same machine, it's on an IP address that
MSSMTP isn't monitoring.

Thanks, guys. Looks like I'll have to find another standalone SMTP server
for outbound mail only.

--
Toby Herring
MCDBA, MCSD, MCP+SB

"Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
news:%23rmV0zEdEHA.216@TK2MSFTNGP11.phx.gbl...
>
> "Jeff Cochran" <jeff.nospam@zina.com> wrote in message
> news:4106c5dd.556806495@msnews.microsoft.com...
> web.
> actually
> resolving
>
>
> Or, some weird DNS resolution problem where the SMTP server thinks that
mail
> for all domains (or the domain in question) should be delivered to
127.0.0.1
> (or whatever IP address is is using)
>
> Cheers
> Ken
>
>

Ken Schaefer

2004-07-29, 2:51 am

You can disable SMTP Socket Pooling:
http://support.microsoft.com/?id=310155
to have MS SMTP server bind to only certain IP addresses

That may help.

Cheers
Ken

"Toby Herring" <therring*@*teletrack.com> wrote in message
news:el%23FJmKdEHA.244@TK2MSFTNGP12.phx.gbl...
> That's most likely what the problem is, then. The MSSMTP server isn't
> configurable enough for me to specifically tell it to watch localhost, but
> no other addresses, and it isn't smart enough to realize that even though
> the target mail server is on the same machine, it's on an IP address that
> MSSMTP isn't monitoring.
>
> Thanks, guys. Looks like I'll have to find another standalone SMTP server
> for outbound mail only.
>
> --
> Toby Herring
> MCDBA, MCSD, MCP+SB
>
>
> "Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
> news:%23rmV0zEdEHA.216@TK2MSFTNGP11.phx.gbl...
to[vbcol=seagreen]
> mail
> 127.0.0.1
>
>

Toby Herring

2004-07-29, 5:54 pm

Does this work for Windows Server 2003 as well?

And it still doesn't explain how to get the service to explicitely bind to
127.0.0.1, when that address doesn't show up in the dropdown box.

--
Toby Herring
MCDBA, MCSD, MCP+SB

"Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
news:%23OTQSyRdEHA.3728@TK2MSFTNGP09.phx.gbl...
> You can disable SMTP Socket Pooling:
> http://support.microsoft.com/?id=310155
> to have MS SMTP server bind to only certain IP addresses
>
> That may help.
>
> Cheers
> Ken

Ken Schaefer

2004-07-29, 8:47 pm

I believe it works in IIS 6.0, since there are no major architectural
changes with the SMTP server.

In any case, I thought you want MS SMTP to listen on a specifc IP address,
not 127.0.0.1

I can't comment on 127.0.0.1 because I don't know which interface/IP address
that loops back to. You will need to test on your machine to see where
127.0.0.1 loops back to.

Cheers
Ken

"Toby Herring" <therring*@*teletrack.com> wrote in message
news:OTC66eYdEHA.3864@TK2MSFTNGP10.phx.gbl...
> Does this work for Windows Server 2003 as well?
>
> And it still doesn't explain how to get the service to explicitely bind to
> 127.0.0.1, when that address doesn't show up in the dropdown box.
>
> --
> Toby Herring
> MCDBA, MCSD, MCP+SB
>
>
> "Ken Schaefer" <kenREMOVE@THISadOpenStatic.com> wrote in message
> news:%23OTQSyRdEHA.3728@TK2MSFTNGP09.phx.gbl...
>
>