Thanks for reading, i have an SMTP server. Also i have two machines one windows server and other in centos server. In windows i configured in xampp to send using my SMTP server and can send mails to anyone,. In CentOS i cant figure it out. I installed sendmail and put smarthost my smtp server, this doesnt require auth(smtp server). but i receive this error(User Unknow) always, can someone try to help me please. i dont know if i have to do something else, as i say i just want to conect to my smpt as i did in windows. Thanks

Now when im trying to send email im getting this log

Aug 7 15:01:40 sr1cloudcenter sendmail[11761]: w77J1bYh011761: from=dcuioit, size=8, class=0, nrcpts=1, msgid=<201808071901.w77J1bYh011761@telconet.ec>, relay=root@localhost
Aug 7 15:01:40 sr1cloudcenter sendmail[11762]: w77J1eue011762: from=<dcuioit@telco.ec>, size=271, class=0, nrcpts=1, msgid=<201808071901.w77J1bYh011761@telconet.ec>, proto=ESMTP, daemon=MTA, relay=localhost [127.0.0.1]
Aug 7 15:01:40 sr1cloudcenter sendmail[11761]: w77J1bYh011761: to=dieggo92@gmail.com, ctladdr=dcuioit (1000/1000), delay=00:00:03, xdelay=00:00:00, mailer=relay, pri=30008, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (w77J1eue011762 Message accepted for delivery)
Aug 7 15:01:40 sr1cloudcen sendmail[11764]: STARTTLS=client, relay=smtpuiod.telco.clo, version=TLSv1/SSLv3, verify=FAIL, cipher=ECDHE-RSA-AES256-GCM-SHA384, bits=256/256
Aug 7 15:01:40 sr1cloudcenter sendmail[11764]: w77J1eue011762: to=<dieggo92@gmail.com>, ctladdr=<dcuioit@telco.ec> (1000/1000), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=120271, relay=smtpuiod.telco.clo, dsn=2.0.0, stat=Sent (Ok: queued as AE2897F16E)

Hi and welcome to LQ,

The logs snippet you've posted looks fine. The message is delivered to the relay smtpuiod.telco.clo (I guess it's the smarthost) for further processing.
Where exactly you get the "User Unknown" error?

Regards

avoid using mail servers: there is no practical reason to be running one on modern PC or unix

(system messages used to go out by sendmail - but no longer, syslog is used and can deliver remotely)

configuration is difficult, www.sendmail.org says how

if yo umake a server you'll likely be blocked (only microsoft, google, verizon get through, the block eveyrone else's smtp at the "big company central level")

you can make a local server: i'm just saying NOT worth it

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your config files have to name your users

for sendmail the users must exist on the system because your running deliver (ie. they go in /var/spool/mail) and fetch can fetch them. to do that (because your running two sendmail servers), your users must really exist. also your config files must map them

you have to make aliases and aliasdb and stuff like that (it don't just work out of the box)

by the way if your making a spam server may you burn in ****

there are scripts to find for senmail that reset senmail. it includes re-making all the db and .cf configs.

the worry is if you make a broken mailer, you'll be getting other peoples mail - and the telephone company will come and seize your computer