From Newsgroup: comp.mail.sendmail

Hi Team,

I am trying to get everything as clean as possible on my sendmail server
as our domain is currently barred by gmail "due to a poor reputation".

Using postmaster tools on google it suggested I needed to fix reverse
/forward dns for my MX records which I have done. All that remains is my certificate error.

I am running ubuntu 20.04 (LAMP) server.

The error from checktls.com is as follows

[006.618] Connection converted to SSL/TLS
SSLVersion in use: TLSv1_3
Cipher in use: TLS_AES_256_GCM_SHA384
Perfect Forward Secrecy: yes
Session Algorithm in use: P-256(256 bits)
Certificate #1 of 1 (sent by MX):
Cert VALIDATION ERROR(S): self-signed certificate
So email is encrypted but the recipient domain is not verified
Cert Hostname VERIFIED (ikserver2.goodnewsbig.com =
ikserver2.goodnewsbig.com)
cert not revoked by OCSP
Not Valid Before: Apr 15 18:05:29 2026 GMT
Not Valid After: Apr 12 18:05:29 2036 GMT
Seconds Until Expired: 315178821
subject: /O=Sendmail/OU=Sendmail Server/CN=ikserver2.goodnewsbig.com/EMAIL=admin@ikserver2.goodnewsbig.com issuer: /O=Sendmail/OU=Sendmail Server/CN=ikserver2.goodnewsbig.com/EMAIL=admin@ikserver2.goodnewsbig.com

Now I have spotted one issue and that is we do not have an "admin" user
on our server currently, but I cannot see how to rebuild the certifcates?

I can see sendmail-{server|client}.cfg files in /etc/mail/tls but have
no clue on how to use them.

I tried reloading sendmail which cured the previous "Cert Hostname"
value being incorrect, but this problem remains.

Can anyone advise or help me please?

Thx Paul

--- Synchronet 3.21f-Linux NewsLink 1.2

From Newsgroup: comp.mail.sendmail

On 17.04.2026 21:30 Uhr pcla56 wrote:

I am running ubuntu 20.04 (LAMP) server.

Unless you have ESM, you do not receive any security updates. Rather
risky.

The error from checktls.com is as follows

[006.618] Connection converted to SSL/TLS
SSLVersion in use: TLSv1_3
Cipher in use: TLS_AES_256_GCM_SHA384
Perfect Forward Secrecy: yes
Session Algorithm in use: P-256(256 bits)
Certificate #1 of 1 (sent by MX):
Cert VALIDATION ERROR(S): self-signed certificate

Try one from letsencrypt and that error should be gone.

Regarding Google, you also need to make sure you have SPF, DKIM and
DMARC properly configured.
--
kind regards
Marco

Send spam to 1776454209muell@stinkedores.dorfdsl.de

--- Synchronet 3.21f-Linux NewsLink 1.2

From Newsgroup: comp.mail.sendmail

pcla56 wrote:

I am running ubuntu 20.04 (LAMP) server.

The error from checktls.com is as follows

Do you mean this:

Cert VALIDATION ERROR(S): self-signed certificate

Ignore it - or pay for a "real" cert (which has basically no advantage
for e-mail except making some "check" websites happy). If you use
Let'sEncrypt you will get a cert which officially isn't usable as
client cert - thanks to some evil company.

Now I have spotted one issue and that is we do not have an "admin" user

Why do you want an "admin" user?

I can see sendmail-{server|client}.cfg files in /etc/mail/tls but have
no clue on how to use them.

Those files are not from sendmail.
Maybe try a mailing list for Ubuntu?

--- Synchronet 3.21f-Linux NewsLink 1.2