Since Firefox tightened the security of their browser it is odd that I can access my control panel exactly as before:
https://12.34.56.78:10000
but attempts to access my mail using:
https://12.34.56.78:20000
are prohibited by Firefox now because it claims the security of the site is not proven.
Yes, I can use Google Chrome, because that alerts you to the fact that it is not covered by a known SSL certificate, but it still allows you to exercise your own judgement and proceed anyway.
However, fine as that is, I don't want to have to ask all my clients to install Chrome just because Firefox has got picky.
Using "netstat -pan | grep 10000" and "netstat -pan | grep 20000" proves it is not an iptables issue.
What is it in the set-up that satisfies Firefox about port 10000 but causes it to gag on port 20000? Why does it allow me to use port 10000 for my control panel but not port 20000 for my mail?
Go to Webmin >> Webmin >> Usermin Configuration.
Select "SSL Encryption"
Click on "Self-Signed Certificate" and finally click on "Copy Certificate From Webmin".
On first use of https://12.34.56.78:20000 you will now get the usual prompt to accept a certificate.
Turns out to be an easy resolution.