eMails with Large Attachments not Going Out

[BytesSolutions]

I have been trying to send emails with attachments over 3Mb, but they get forever stocked into MS-Outlook 2007 "Outbox" folder. I am using a POP3 account (using SMTP port 25 for outgoing mails) from my web hosting supplier (this is not an internal mail service).

I have tried increasing the Message Size Limit at Spam Blocker, have turned it off, even removed it and reinstalling it. But still same issue persists.

If I connect from outside my location (not behind UT) all these mails flows with no issue at all.

I have tried searching the forum, but even when I have found some similar cases, and followed some instructions, I have not solved the issue yet.

I'm currently running Untangle 9.1.1 version.

I also have a customer running same version which UT box can not send reports out. So I am guessing this should be a similar issue due to the report attachment size.

Thank you in advanced for your help.

[sky-knight]

Untangle's SPAM module auto-whitelists all outgoing SMTP 25 by default. So unless you're plugged in backwards with an Untangle bridge, the SPAM filter isn't affecting anything.

Some SMTP servers do have a size limit, and that is a common enough occurrence for Untangle when sending reports. View the contents of /var/log/exim4/mainlog for details, it will give you the specific SMTP error message when Untangle sends any mail, so you can stop guessing and start fixing!

[BytesSolutions]

I have loked into the mainlog trying to find any specific SMTP error which is avoiding me to send emails with big attachments, but I have not found anything.

Basically the log file shows the following:
2012-02-03 12:21:36 Start queue run: pid=5701
2012-02-03 12:21:36 End queue run: pid=5701
2012-02-03 12:51:37 Start queue run: pid=13810
2012-02-03 12:51:37 End queue run: pid=13810
2012-02-03 10:21:36 End queue run: pid=4594
2012-02-03 10:51:36 Start queue run: pid=12295

If I connecto the Internet outside my network (not behind UT) imediatelly these mails go through. They only get stocked when I'm behind my UT box.

My configuration is: Internet---> Cisco 857 Router---> Untangle 9.1.1 (Bridge Mode) and I have checked how the network cables are connected between the router, the UT box and the network switch and they are okay.

Any suggestions?

[sky-knight]

Have you tried manually bypassing stuff destined for TCP 25 and sourced from the internal IP address of your mail server?

As to getting Untangle to send you reports, make sure it's configured to use your mail server as the SMTP server, and use the local IP not the name! Make an account, or configure the mail service to trust stuff coming from UT's local interface IP.

[johnsonx42]

it's probably the delay caused by the virus scanner timing out outlook.

I had recently tried un-bypassing port 25 outbound on a client's UT, and the results were not pretty. In my case, the result was that e-mails with even moderately sized attachments would be delivered to the recipient, yet the delay would be just long enough that the SMTP send daemon would timeout and think the message was not delivered, so it would queue the message for re-delivery which it did over and over and over again. They got a few angry e-mails "why the %$(*# are you sending me a dozen copies of the same e-mail!?!?!?!?"

best to just bypass port 25 outbound and be done with it.

[BytesSolutions]

How I can configure a bypass for port 25 outbound from virus scanner (from virus blocker and virus blocker lite?

I have not found that option.

Thanks in advanced!

[BytesSolutions]

I am not using an internal email server, instead I'm using POP/SMTP and MAPI accounts.

[jcoffin]

To bypass outgoing SMTP, Config -> Advanced -> bypass rules. Add rule:

- Source Interface : Internal
- Destination Port 25

[BytesSolutions]

Guys, sorry for not posted out the results before!

But it definitelly works. I followed Jcoffin steps above and the issue was fixed.

Thank you all for your suggestions.