[AusNOG] Issues receiving from TPG Mail servers.

[Scott Howard]

On Mon, Jul 23, 2018 at 10:00 PM, Paul Wilkins <paulwilkins369 at gmail.com>
wrote:

> One thing you might check is the cipher set you're using.
>
> I can connect to https://tpg.com.au with TLS1.2 just fine.
>

What they support on HTTPS/port 443 isn't all that relevant for email
delivery...


> openssl s_client -connect mx1.tpgi.com.au:465
>

Again the original thread was about receiving emails, so port 465 plays no
part.  In fact, there's no way to explicitly test what they support when
sending emails (other than actually having them send an email and watching,
obviously), but he nearest would be to see what their MX records support on
port 25.

The command to test that would be :
$ openssl s_client -connect mx1.tpgi.com.au:25 -starttls smtp -tls1_2

which fails as they don't support TLS 1.2.  The same command for TLS1.1
also fails, whilst TLS1.0 succeeds.
(This presumes they use the same systems/config for inbound as outbound,
but that's generally a fairly safe bet)

  Scott
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