[Users] Autoconfig does not support port 465 in SRV record

[Jack]

Hello,

Virgin Media uses SSL/TLS on port 465 for email submission via SMTP:

$ dig _submission._tcp.virginmedia.com -t SRV +short
0 1 465 smtp.virginmedia.com.

https://help.virginmedia.com/system/templates/selfservice/vm/help/customer/locale/en-GB/portal/200300000001000/article/HELP-2203/Email-Settings-for-all-Virgin-Media-domains

Claws Mail supports SRV records for autoconfiguration. Unfortunately, it always assumes that STARTTLS (=explicit SSL/TLS) is used for SMTP. But in this case I need implicit SSL/TLS on port 465.

I would like to suggest that the autoconfig wizard in Claws Mail tests if STARTTLS works for SMTP. If it doesn't, it should try implicit SSL/TLS.

If this is not possible to implement, I suggest that implicit SSL/TLS is always used for port 465. It is very unlikely that someone would be running STARTTLS on port 465. Ports 25 and 587 are commonly used for STARTTLS.

[Andrej Kacian]

On Mon, 10 Apr 2017 12:20:14 +0200

Post by Jack
Hello,
$ dig _submission._tcp.virginmedia.com -t SRV +short
0 1 465 smtp.virginmedia.com.
https://help.virginmedia.com/system/templates/selfservice/vm/help/customer/locale/en-GB/portal/200300000001000/article/HELP-2203/Email-Settings-for-all-Virgin-Media-domains
Claws Mail supports SRV records for autoconfiguration. Unfortunately, it always assumes that STARTTLS (=explicit SSL/TLS) is used for SMTP. But in this case I need implicit SSL/TLS on port 465.
I would like to suggest that the autoconfig wizard in Claws Mail tests if STARTTLS works for SMTP. If it doesn't, it should try implicit SSL/TLS.
If this is not possible to implement, I suggest that implicit SSL/TLS is always used for port 465. It is very unlikely that someone would be running STARTTLS on port 465. Ports 25 and 587 are commonly used for STARTTLS.

Fixed in git, even though technically this is incorrect. See the
relevant commit message for details:
http://git.claws-mail.org/?p=claws.git;a=commitdiff;h=dbec2c

Regards,

[Jack]

Hello Andrej,

Thanks for your support! I agree that port 465 is no longer an official standard for SMTP. But there are ISPs that still use the port.

Some background info:

https://en.wikipedia.org/wiki/SMTPS
https://en.wikipedia.org/wiki/Opportunistic_TLS#Weaknesses_and_mitigations
https://www.fastmail.com/help/technical/ssltlsstarttls.html

---
Jack