Librem One SMTP recently hangs with ProtonVPN on

Services Librem One
1

Since ProtonVPN ‘help’ desk only advise me to keep trying an unspecified number of US and ex-US servers, I’m posting this here in case it is better known to Librem One users.

In the last few weeks, SMTP hangs when ProtonVPN is connected. As soon as I disconnect ProtonVPN, I can send the mail. This is a new problem, and I have made no changes to the default configuration I get from Thunderbird. Receiving mail is unaffected.

Advice on troubleshooting also appreciated. Are there logs could I inspect?

2

With the VPN connected does all SMTP hang or only SMTP to the Librem One SMTP server?

Refer https://wiki.mozilla.org/MailNews:Logging#Main_module_options_within_MailNews item 16 for enabling SMTP logging in Thunderbird.

Any chance that the VPN is blocking port 25 outbound? What port are you attempting to use for SMTP anyway?

1 Like
3

Thanks for tip on Thunderbird logging, and also reminder (oops!) to check my several SMTP servers.
As it stands, the issue affects a non-librem.one SMTP server as well, so not a Librem One issue.
Nor is it port-specific.
Accordingly, will mark your reply as Solution.

4

Almost all non-enterprise connections block outbound from the customer port 25 to help with spam. I’m surprised you were on a connection that was allowing it to work in the first place :slight_smile: Always configure your mail clients for sending smtp on port 465 or 587 depending on what your server supports.

5

To be clear, neither of my SMTP servers was using port 25.
They are set up to use 587 + STARTTLS and 465 + SSL/TLS.

6

ahh perfect ok, so it was just the protocol itself! Carry on… :slight_smile:

7

Not if you use a VPN …

Hmmm. OK. I didn’t see an actual solution there. It suggests that the problem is not with the SMTP server though.

1 Like
8

Exactly. It’s a ‘solution’ at least inasmuch as it excludes any Librem-specific issue.
I expect these logs will help me debug, and maybe elicit better help from Proton.

9

OK. My starting point would be to determine whether the TCP connect fails or whether the TCP connect succeeds but the SMTP session fails later on.