[Users] Claws Mail Can't Connect to Internet With Specific Internet Connection

[Dustin Miller]

On Tue, 11 Oct 2022 15:47:39 +0200
Paul Rolland <rol at witbe.net> wrote:

> On Tue, 11 Oct 2022 19:38:18 +0600
> Dustin Miller <dustbiz at gmail.com> wrote:
> 
> > In any case, I am wondering whether anyone (probably a developer)
> > can give me a basic idea of what is supposed to happen (i.e.
> > 'behind-the-scenes') in the interaction between CM and its host
> > system (Linux-based) when a person directs CM to check email? Or
> > perhaps point me to a resource or documentation where I could find
> > this out myself? Might be a long shot, but I thought I'd check in
> > here to see if I can get some info that will help me know how to
> > move forward with trouble-shooting this.  
> 
> You can use openssl to test (exemple with POP3):
> 
> 187 [15:44] rol at riri:~> openssl s_client -host riri.xxx.xxx -port 995
> 
DM: Thanks, Paul R, it's quite helpful to know about this method of
testing. With the 'okay' connection and using 'pop.gmail.com', I got
what looked like expected output without any noticeable errors. With
the 'problem' connection, I got no output at all. I also tried
'smtp.gmail.com' with port 587 on the 'problem' connection; once again,
no output (on the 'okay' connection it gives output w/o any errors).
(BTW, previously I had also tried unchecking the box related to
non-blocking TLS in the Claws settings, but that didn't help either.)

DM: I'm not sure what to gather from these results. Does it mean that
the problem is likely something local on my system before there is any
connection to the internet? Or is it still possible that it could be an
issue outside of my system (local network device settings, or ISP
settings)? Thanks again, ---Dustin