I need to know how much data are transmitted on my ppp0 network or eth0 Internet links? How do I set IP accounting by address such as 18.104.22.168 and 22.214.171.124? How do I set IP accounting per Apache virtual domain? How do I set accounting by service port (http, smtp) and protocol (tcp, udp, icmp)? How do I record how much traffic each of the clients computer is using?
I can send and receive mail using firstname.lastname@example.org, but system generated emails such as email@example.com bounce backup with an error:
May 1 03:14:52 mail postfix/smtp: 23CA4BD6B40: to=
, relay=none, delay=0.01, delays=0/0/0/0, dsn=5.4.6, status=bounced (mail for mail.example.com loops back to myself)
How do I fix this error?