Spam Filter ISP Support

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smart host

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=6352
Printed Date: 31 October 2025 at 12:14am

Topic: smart host

Posted By: hookjd
Subject: smart host
Date Posted: 15 January 2008 at 11:48pm

Hey there. I would like to know if I can configure an Exchange server to send outbound smtp through spamfilter. Exchange does not allow for authentication when doing this, but you can set email to send through a smart host at an IP address. I attempted to add my IP address to the whitelist, but it does not allow me to send to a non-local domain this way. I get the "no relay allowed" error in the logs. I believe this should be possible, but I can't seem to find any good documentation on this feature. I am running the Enterprise version. Thanks.

Replies:

Posted By: Desperado
Date Posted: 16 January 2008 at 10:22am

hookjd,

The error you are getting is actually correct as spamfilter is designed to accept messages for only the domains it is authorized for. Anything else would be an open relay. Also, SpamFilter is not intended to send mail to the "outside World". Perhaps the question I want to ask is "why"? What is it you are attempting to accomplish?

-------------
The Desperado
Dan Seligmann.
Work: http://www.mags.net
Personal: http://www.desperado.com

Posted By: hookjd
Date Posted: 16 January 2008 at 12:14pm

Well... are you sure? I understand the purpose of SpamFilter as I've been using it for years, but I do believe a method was added a while back to allow authenticated users to use spamfilter to relay email.

ie: http://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=6285&KW=relay&PID=11100#11100 - see this thread .

That thread even makes it sound like I should be able to whitelist an IP to relay, but that doesn't appear to work for me.

My reasons are that I personally operate an Exchange server at my office and recently switched to a new block of IPs through Charter that were blacklisted when I received them. So I need to have Exchange relay my outbound mail through a legit mail server until I can get my IPs off the blacklists. I have used smarthosting with other mail servers in the past, but since the IP of my spamfilter install would likely never ever be on a blacklist, it seems like a great option to relay my outbound mail. Thoughts?

Posted By: Desperado
Date Posted: 16 January 2008 at 12:52pm

hookjd,

It is true that SpamFilter will authenticate but where will it relay to is the issue (I think). If I authenticate in (Let's forget that Exchange will not authenticat for the moment), SpamFilter will want to forward to the server specified in the ini file which, in this case, I assume is your exchange server. This will cause a confusion, I would think.

However, having said all that, if you add the *root* ip of your exchange server into the allowedIP list, SpamFilter should accept it and attempt to forward it. If it forwards to your exchange server, I believe Exchange will reject it based on not understanding the domain it was sent to and loop back. Is that what is happening?

-------------
The Desperado
Dan Seligmann.
Work: http://www.mags.net
Personal: http://www.desperado.com

Posted By: __M__
Date Posted: 16 January 2008 at 5:22pm

hookjd, just to throw my 2 cents worth in:

We use Exchange ourselves for our own company mailserver, we have set our Exchange to forward mail to our SFI box and simply added our Exchange Server's IP in the IP Allowed List and even set No Authentication to be necessary (currently only IPs in Allowed List are internal IP). As we host mail services for many of our customers it made sense to have Exchange send mail to SFI which then sends it out to the customer's mail server rather than having the mail go to the internet then back into our SFI.

Email recipients who are not hosted by us are simply relayed out through another mailserver. I'm not sure if the same sort of setup would work for you but it's a very good solution for us.

On a side note this has also enabled us to simulate the flow of mail to customer mail servers prior to changing MX records to flow through our SFI (great for provisioning new servers).

Posted By: hookjd
Date Posted: 16 January 2008 at 8:21pm

Well I'm confused how you set that up. It seems that on my Exchange box I only have one option. To forward all outbound mail to be relayed through another IP address. But your description sounds like you are sending some mail outbound through SFI and some through regular DNS lookups directly to outside mail servers... Me confused.

Ultimately, though I just want to know if I can use SFI as a smarthost to send to domains that are not in the "local domains" on SFI. Roberto? Can you confirm or deny?

Posted By: LogSat
Date Posted: 17 January 2008 at 9:42pm

hookjd,

As Dan correctly states, SpamFilter can be used to relay emails addressed to "the internet" (meaning to domains that are not in the "Local Domains". To do this, either the sender's IP address needs to be added to the P whitelist, or you can use SMTP Authentication to authenticate the username of the sender.

Please do note however that SpamFilter will never forward emails to the internet directly. All emails in the above scenario wil be forwarded to your default "Destination SMTP Server" as configured in SpamFilter's Settings - Configuration tab. If this destination SMTP server is the same one that has SpamFilter configured as a smarthost, you'll be likely creating emails loops between SpamFilter and your Exchange server (Exchange uses SpamFilter as a smarthost, SpamFilter will then forward the emails back to Exchange, Exchange will then forward the to the SpamFilter smarthost, etc etc).

-------------
Roberto Franceschetti

http://www.logsat.com" rel="nofollow - LogSat Software

http://www.logsat.com/sfi-spam-filter.asp" rel="nofollow - Spam Filter ISP

Posted By: hookjd
Date Posted: 17 January 2008 at 11:17pm

OK, so all my initial assumptions were correct. However. I had already added my IP to the IP whitelist, but when I tried to send mail through it gave me the error of "non-local domain or % in address". I am using the Enterprise version, so I added my IP to the whitelist for "ALL DOMAINS". Do I need to add it to the whitelist for the other domains that I have set up as customized? Or do I need to add it to some other IP whitelist than the one I am mentioning?

Posted By: hookjd
Date Posted: 17 January 2008 at 11:18pm

Also, fyi. Every time I post on your forums I get an ASP error. The post works, but the response page indicates an error.

Microsoft OLE DB Provider for SQL Server error '80004005'

Could not find server 'BACOLI' in sys.servers. Verify that the correct server name was specified. If necessary, execute the stored procedure sp_addlinkedserver to add the server to sys.servers.

/spamfilter/forums/new_post.asp, line 1085

Posted By: hookjd
Date Posted: 17 January 2008 at 11:36pm

Actually the key to this whole thing is in your last post. Since you said it doesn't really forward out to the internet, but just to my "destination smtp server", then what I am trying to do won't work. Thanks for the clarification.

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