My server host sent me this message:
80 failed/unauthorized logins attempts via SMTP/IMAP
We have detected abuse from the IP address
xx.xxx.xx.xx
, which according to a whois lookup is on your network.Jan 31 07:24:30 server postfix/smtpd[12371]: warning: unknown[xx.xxx.xx.xx]: SASL LOGIN authentication failed: authentication failure
Can someone please let me know where to begin looking at for this?
I already installed Fail2Ban and modified my hosts.allow
which was previously sendmail:all
and I changed it to sendmail:localhost
But both the above methods so far seem ineffective.
I am using Ubuntu 14.04
.