To reduce the amount of spam sent to Gmail

Since many today have an issue with the gmail blocking them in case of the spam, here is a short info about it. If you see in your postfix log file /var/log/maillog messages like: Mar 29 08:13:02 cwp-mailserver postfix/smtp[12934]: A35C2137013: to=, relay=gmail-smtp-in.l.google.com[173.194.69.26]:25, delay=1.1, delays=0.1/0.02/0.61/0.34, dsn=5.7.1, status=bounced (host gmail-smtp-in.l.google.com[173.194.69.26] said: 550-5.7.1 [85.111.34.35 12] Our system has…