My server is sending spam with an IP address that emulates that of my server

[menteinfinita]

For several days now, my server is throwing more than a thousand spam emails with different accounts using an ip and validating itself as if it were my IP, I already have that IP blocked inbound and outbound, even in firewall and still sending spam. The bad IP is: 1624 173.194.208.28

SMTP Activity

03/01/19 08:49:48 SMTP-OU 6C18B097359E4DE7961B234CC50BF7CD.MAI 1624 173.194.208.28 EHLO EHLO mail.publi-server2.com 250-smtp-relay.gmail.com at your service, [107.XXX.XXX.XXX] 29 177
03/01/19 08:49:48 SMTP-OU 6C18B097359E4DE7961B234CC50BF7CD.MAI 1624 173.194.208.28 MAIL MAIL FROM:<ventas@midominio.com> SIZE=1812 250 2.1.0 OK a5sm1968860otl.1 - gsmtp 46 39
03/01/19 08:49:48 SMTP-OU 6C18B097359E4DE7961B234CC50BF7CD.MAI 1624 173.194.208.28 RCPT RCPT TO:<191512767@qq.com> 250 2.1.5 OK a5sm1968860otl.1 - gsmtp 28 39
03/01/19 08:49:48 SMTP-OU 6C18B097359E4DE7961B234CC50BF7CD.MAI 1624 173.194.208.28 DATA DATA 550-5.7.1 Daily SMTP relay limit exceeded for customer. For more information on 6 253
03/01/19 08:49:48 SMTP-OU 6C18B097359E4DE7961B234CC50BF7CD.MAI 1624 173.194.208.28 QUIT QUIT 221 2.0.0 closing connection a5sm1968810otl.1 - gsmtp 6 55

I do not know how I can block this.

SMTP Debug
03/01/19 08:37:27 ME-IXXXX: [D5D088DC9AAA490A93190B254373C4FE.MAI] DNS resolved to the following record: IP Address=74.125.197.28, Family=2, Type=1, Protocol=6

Please Help me!!!

[MailEnable-Ian]

Hi,

The log snippet reports SMTP-OU and therefore the IP address listed is the remote mail server your sending to. You need to search further up in that log file for the associated SMTP-IN and block the incoming IP listed there. Add the IP address to the SMTP "Access control" list under the option for "Granted all expect those in the list".

[menteinfinita]

Thank you very much for the track. In the end I could finally find the account, just enter the inbound connections and outbound connections and there I could see who was the guilt of spam. Thanks so much.