I am currently testing several scenarios where I use the UTM as email gateway. The UTM is not acting as firewall.
Basic problem seems to be that my VDSL provider (Swisscom) decided to ban port 25 from the internet they provide to me. I have instead to use port 587 for each email I send, for any mailhoster (i.e. gmx.net, etc.), even if it's not located on the Swisscom net. See Help - Spam Filter Port 25 | Swisscom.
Anyway, my problem is that I:
1 - cannot see in any log what exactly happens when the UTM is forwarding emails to an outside SMTP server. I do have to wait for the UTM to generate an error message and send it back to the orginator. Is there anywhere a logfile which would show the connection attempts made from UTM to the routing host? Similar to what I see on incoming emails in SMTP live log?
2 - I seem not to be able to configure UTM to use port 587 instead 25 to forward email. I did try with the smart host setting, using port 587, but that does not work either. In any case, I anyway cannot use the smarthost setup for all my emails, since I intend to create several profiles.. see below.
This is how my setup looks like:
- I have an email hosting on hoststar (this is a hosting provider) for the email address "test1@utm.cu.cc".
- I send test messages either from gmail or gmx to the test address "test1@utm.cu.cc"
- utm is setup on a local LAN as VMware appliance
- the firewall (fritzbox) passes ports 25, 587, 465 from the WAN interface through to the UTM on the LAN
- DNS server for utm.cu.cc is located on hoststar as well
- I redirect mails with an MX record for utm.cu.cc that points towards the WAN interface of my LAN where the UTM resides
- On the UTM, I configured an SMTP profile that forwards the emails further (routing, static host, IP address) to the hoststar where the email should be delivered into the hosted mailbox.
- I made sure that I do not create a mail loop. On hoststar, if you deliver email to an IP address, it is immediately put into the mailbox, even if the DNS MX record on the same host points to another host.
Expected Email flow:
Part 1:
gmail --> DNS MX lookup for utm.cu.cc --> WAN of firewall --> passed through to LAN and the UTM
..... at this moment, I can see the email arriving on the UTM in the SMTP proxy live log. However, I do not see in the same log that the email is forwarded...
Part 2:
UTM --> hosting provider machine IP --> mailbox
..... the problem lies in Part 2. According to returned emails, the forwarded email never arrives at the providers mailbox, as it is "hijacked" by that strange Swisscom rule to not let pass emails on port 25...
the returned email looks as follows:
This message was created automatically by the SMTP relay on utm.
A message that you sent could not be delivered to all of its recipients.
The following address(es) failed:
test1@utm.cu.cc
SMTP error from remote mail server after RCPT TO::
host []: 573 573 Swisscom Antispam:
Authentifizierte Verbindung nicht moeglich. Bitte benutzen Sie den Port 587 anstelle von Port 25. Weitere Informationen:
www.swisscom.ch/p25. Connexion authentifiee pas possible. Veuillez utiliser le port 587 a la place du port 25. Ulterieurs informations:
www.swisscom.ch/p25. Collegamento autenticato non e possibile. Si prega di utilizzare la porta 587 invece di porta 25. Altra informazione:
www.swisscom.ch/p25. Authenticated connection is not possible. Please use port 587 instead of port 25. More information:
www.swisscom.ch/p25.
------ This is a copy of the message, including all the headers. ------
[...]
so, to summarize, it seems that I need to be able to tell the UTM to use port 587 instead port 25 when forwarding (routing) emails to a static host IP.
I would have expected that at least with smarthost enabled, I should be able to forward emails. But it apparently fails. And since I cannot look into a connect log of some sorts, i cannot find enough details.
Can anyone help me here?
Thanks
Dan
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