Topic: Why are sent emails blocked by Dansguardian?

[ben2church]

POP3 emails aren’t being delivered outside of my network.  From Outlook Express, they say that the emails have been sent and everything is normal, but the emails aren’t arriving anywhere.  No one receives them and OE doesn’t get emails saying the emails are being returned or rejected.  Can receive email just fine.

Before I go on, my setup:  SME Server, with Dansguardian installed, but not turned on, in private server-gateway mode.  We do not use the server for email or even fetchmail, only internet routing and roaming profiles.  Email accounts are through our hosting service who hosts our website, and a few accounts from our broadband connection, Road Runner (Time Warner).  They are all POP3 accounts from Outlook Express.  I ran SME server for several weeks before installing Dansguardian, and emails ran perfectly.

Problem occurred when trying to install Dansguardian, which was successful, but has been turned off for now.  I followed the step-by-step instructions by Ray Mitchell, and installed.  I did everything, including changing the SME port to 8080.  After this point, emails that were sent wouldn’t be delivered anywhere.

To try and fix the problem on my own, I turned off Dansguardian, tried manually setting all windows connections to automatic, port 8080, port 3128, and manually setting it to the SME IP address (I have tried all IP possibilities that exist on the SME server).  I can always connect to the internet from any station without any trouble.  I went back and reset the SME port back to 3128, hoping that would solve it, but no.

What am I missing??  It has to be something related to Dansguardian, because that is when the trouble started.  Is there a setting I am missing to allow emails to go out?  If it is a setting associated with Dansguardian, why doesn’t it allow emails to send out when I stop the Dansguardian program?

Any help anyone can give would be helpful.

Thanks!

[raem]

ben2church

It doesn't sound like a problem that Dansguardian will cause. Web content filtering, transproxy port settings and mail flow are quite different things.

Think hard , what else did you change.

If you still wish to "blame" dansguardian then completely remove it from your system, it's just s few minutes to uninstall
rpm -e packagename
set the transproxy back to 3128 etc etc


> Is there a setting I am missing to allow emails to go out?  

Well it sounds like your smtp proxy port may be the issue. If you are trying to use an external mail server and wish to connect to that to send mail, then you need to disable smtp proxy, search here for how to do that. It's in the release notes for sme 6.0.

> POP3 emails aren’t being delivered outside of my network.  

POP is a receiving protocol, smtp is a sending protocol, so you will never send POP3 emails !

> From Outlook Express, they say that the emails
> have been sent and everything is normal, but the
> emails aren’t arriving anywhere.  
>.... private server-gateway mode.  
> We do not use the server for email.....
> Email accounts are through our hosting service


What setting for smtp server are you using in OE ?

[ben2church]

Sorry for the late response.  It was in fact not Dansguardian that was the problem.  Just happened that I was told of the problem the day after I installed Dansguardian and assumed they were related.

The problem was the smtp.  The post I found that worked was at http://forums.contribs.org/index.php?topic=22221.msg88142#msg88142

This worked well for me!  To repeat for anyone else who has had to sifted through the million smtp posts, here is the quote I used for OE:

After a whole lot of searching...I came across the following to fix my problem as so many others have been having......the inability to send out mail without having SME pickup the traffic on port25, therfore casuing errors.

/sbin/e-smith/config setprop smtpfront-qmail Proxy disabled
/sbin/e-smith/signal-event remoteaccess-update
/etc/e-smith/events/actions/restart-masq

Done.....now I can send out mail using 3 different ISPs SMTP servers without any problems.
Hope that helps the masses, as I am a newbie and can't really back this up much other than saying that it worked for me.

Allan

Thanks to Allan and thanks to Ray for his expert advice.

Ben

[raem]

ben2church

> The problem was the smtp.....
>.....now I can send out mail using 3 different ISPs > SMTP servers without any problems.

The problem was not the smtp, it was how you setup your email clients.

By disabling the sme server smtp proxy and not sending email via the proxy, you do loose the protection that the smtp proxy gives your network ie in the event of a localised virus infection on a workstation, then the virus can now broadcast its messages directly to the Internet using its own hard coded smtp server engine.

In the event that the sme server smtp proxy was  still enabled, then the virus's smtp engine cannot send directly to the Internet, and it doesn't know about the location of the smtp proxy so cannot use that, therefore you stop the flow of thousands of outgoing virus infected messages. You also stop the possibility of gettimg your server IP blacklisted as being a spammer.
 
The ideal way to configure email clients that "need" to talk directly with their ISP's POP servers (for download only), is to configure the POP server setting with the ISP's details eg
mail.ispdomain.com
and configure the smtp server setting as the sme server eg
mail.mydomain.com
and of course leave the smtp proxy server enabled.

That way mail is directly polled and received from the ISP via POP but is sent via your server's SMTP server.

You also have the possibility of nominatimg an outgoing ISP as the smtp server in the server manager email panel, but this is generally not needed.
It only provides the option to send ALL mail via your ISP's smtp server. In this case you would still specify your sme smtp server details in local email  clients & avail of the protection of the smtp proxy.

Of course the above doesn't apply if for some technical reason you MUST send outgoing mail from email clients directly via MULTIPLE DIFFERENT ISP's smtp servers. In that case you will need to disable the smtp proxy.


> Hope that helps the masses, as I am a newbie and
> can't really back this up much other than saying
> that it worked for me.

Of course disabling the smtp proxy will work, but it's not the best/correct answer is many/most cases, although the only answer in some cases.
You should not disregard why the design decision was made by the developers to include a smtp proxy and what you loose by disabling it.