# Google Mail bounces email sent via IPv6, while this works ok with IPv4.
#
# Convert Google Mail IPv6 complaint permanent error into a temporary error.
# Turn 550 error containing gsmtp in the message into 450 error.
# This way Postfix will attempt to deliver this e-mail using another MX
# (via IPv4).
#
/^5(\d\d )5(.*information. \S+ - gsmtp.*)/ 4${1}4$2
