I am wondering is this entry in auth.log something that I should be concerned about
Feb 22 12:18:25 host1 auth: pam_unix(dovecot:auth): check pass; user unknown
Feb 22 12:18:25 host1 auth: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=swann rhost=50.227.181.106
Feb 22 12:19:37 host1 saslauthd[2055]: pam_unix(smtp:auth): check pass; user unknown
Feb 22 12:19:37 host1 saslauthd[2055]: pam_unix(smtp:auth): authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=
Feb 22 12:19:38 host1 saslauthd[2055]: DEBUG: auth_pam: pam_authenticate failed: Authentication failure
