A client of mine is running SME 9.2 in server only mode. The SME server provides DHCP, email, and file services, with a router handling the internet connection. All users either use Mozilla Thunderbird on PC’s/laptops or the stock clients on Android and iphones/ipads. The SMTP settings used are mail.mydomain.co.uk SMTP Port 465, SSL, Normal password. Everything works fine. The SME Server IP address is 192.168.0.250, with the router being on 192.168.0.1
They also have a server on the network that runs their accounts software supplied by ‘Acme Accounts’ (a made up name). This has been set up with a static IP 192.168.0.20. I did not add this to the hostnames in the server manager, as there was no need as it ran independently of the SME Server.
One of the functions of the accounts server is to email invoices out to clients, and this has worked fine up until recently when some customers reported that they were not receiving emails. My client spoke to Acme Accounts, and they suggested that it may be because the mail server being used was the one hosted by the Acme accounts, and it may help to switch to my client’s own email server. I was asked to supply log in details so the accounts server could send email via SME Server.
I created an account on the SME server, and tested it both internally and externally using Mozilla Thunderbird on a PC. It works fine.
However, when they tried it on their software they got a timeout with the following error:
2019-11-05T16:01:02.163134+00:00 mtl postfix/smtp[22580]: 2E9C312E30F: to=<kevin@acme.co.uk>, relay=mail.mydomain.co.uk[82.69.37.28]:465, delay=519, delays=219/0.01/300/0, dsn=4.4.2, status=deferred (conversation with mail.mydomain.co.uk[82.69.37.28] timed out while receiving the initial server greeting)
This told me that the Acme server was accessing the SME Server over the internet, rather than locally, however they reported that if they used port 25 with the login details they could send emails to local addresses, but not to external ones.
I suggested that they change their DNS settings to use the SME server (as all other clients do), and I created a hostname on the SME server for the Acme server with its MAC address and IP address. I also suggested that they try using STARTTLS with port 25 to see if that made any difference.
They have tried all of this, and have got nowhere. The last message I had from them was:
I’ve tried every combination of the available details (we can only use SSL or TLS not STARTTLS – that I am aware of anyway) and at present we have come full circle, with a time out while talking to that mail server.
I closest I get to it working is on port 25, with TLS turned on, using the authentication details. It gets to talk to the server, which then gives back a relaying error.
Normally when we see that talking to an exchange type server it is because the Acme server need to be whitelisted on the exchange type server to be allowed to relay email through the server as an external mail client. Their normal default stance is to only allow client to talk to them and not to allow other mail systems to send via them.
I think the Acme server is Linux based, but I’m not sure, so I have asked for what software they use to send emails, and also a copy of some of the bounces they are getting.
Any help would be greatly appreciated, thanks.