relay.plus.net down?

[#1]

For the past two days, my homelab Exchange server which has been using relay.plus.net for years has started returning message delayed errors. I tried pinging relay.plus.net from both my local network and an online ping service and it appears to be down.

ping -c3 relay.plus.net

PING relay.plus.net (212.159.8.107): 56 data bytes

Request timeout for icmp_seq 0

Request timeout for icmp_seq 1

--- relay.plus.net ping statistics ---

3 packets transmitted, 0 packets received, 100.0% packet loss

Is there an ETA for this being restored?

[#2]

The relay servers do not respond to ping requests from what I can establish.

I am able to connect to the server on port 25 so I've no reason to believe there's anything wrong with it at the moment. What port is your exchange server using, and are you using authnetication and/or TLS/SSL?

bob@thinkpad-l450:~$ ping relay.plus.net
PING relay.plus.net (212.159.8.107) 56(84) bytes of data.
^C
--- relay.plus.net ping statistics ---
37 packets transmitted, 0 received, 100% packet loss, time 36867ms

bob@thinkpad-l450:~$ telnet relay.plus.net 25
Trying 212.159.9.107...
Connected to relay.plus.net.
Escape character is '^]'.
220 avasout-ptp-004 smtp relay.plus.net

[#3]

None of the Plusnet servers have responded to pings for years - all part of reasonable security measures and performance optimisation.

That said sometimes the responsiveness of the mail servers can be slow - I suspect it is a matter of which one of the servers in the server farm one connects to.  None of these services are a single instance.

Try increasing the server timeout setting in your email application.

[#4]

My send connector (Exchange 2019) is still working OK on port 587, basic authentication, and the TLS box checked.

You have to use PowerShell to change the port, everything else is in ECP.

[#5]

Port 587 should be STARTTLS

Deprecated port 465 will run TLS/SSL