We continue to track the intermittent connections in Zambia. They simply don’t make sense. For example, some MTN customers have no problems connecting, but some do. And some people can connect on MTN, but not Realtime/HAI, or they can connect on Paratus, but not MTN.
But we are slowly managing to narrow things down with a resolution in mind.
We did receive a call from a client who has talked to at least one ISP up on the Copperbelt, and they informed him that they allow some connections but not others, and they allow some connections intermittently such that it works one minute and stops working the next. This is exactly the behaviour our clients are seeing, and it seems to be intentional on the part of at least one Zambian ISP! Now, these are very vague statements, but our client asked us for an email explaining how our system works and is configured that he could send to them. Herewith a copy of our email:
Thanks for your phone call. As I said on the phone, this mail server operates in exactly the same way as the old mail server. There is simply no way to operate a mail server on the Internet that does not conform to the same interoperability standards as every other mail server on the Internet. Sure, the are minor variations on how some things are done internally on all servers, but for server A to talk to server B and deliver an email — or for a personal computer or phone to get that email to server A in the first place — they all have to be talking the same language.
Also, I find it very difficult to understand an ISP saying that they allow some standard behaviour and disallow other standard behaviour. And it’s even more bizarre that they say they allow some behaviour intermittently; what’s the point of that?!
With that editorial out of the way, this is the configuration of both the old and new mail servers:
SOFTWARE:
- MTA (mail transfer agent, i.e., mail server software, SMTP): Postfix
- MDA (mail delivery agent, i.e., POP and IMAP): Dovecot
- Web server (control panel and webmail): Nginx
PORTS (all TLS/SSL):
- POP: 110/995
- IMAP: 143/993
- SMTP: 587
- Web: 443
This is a 100% standard configuration, and as I’ve said before, is exactly the same as it was on the old server … EXACTLY the same.
Any ISP is welcome to contact me directly, by email or phone, to explain why users on our system should be subject to some sort of arbitrary blocking of anything. And they’re welcome to contact me just to ask questions or for a friendly chat. Everyone in the world (barring repressive dictatorships, which I don’t think Zambia has become just yet) uses these same port numbers and configurations.
Please keep me informed. Thanks.
Craig
