I wanted to put google's outbound SMTP servers on a postscreen whitelist, but the list seems to be dynamic. I found this web page that explains how to get the list of IP addresses: http://support.google.com/a/bin/answer.py?hl=en&hlrm=de&answer=60764
So I wrote a quick script that outputs to stdout the list of CIDR addresses in a format suitable for a postscreen whitelist. The script is called gwhitelist.sh and is available here: http://archive.mgm51.com/sources/gwhitelist.html The output from the script currently is: # gwhitelist.sh 216.239.32.0/19 permit 64.233.160.0/19 permit 66.249.80.0/20 permit 72.14.192.0/18 permit 209.85.128.0/17 permit 66.102.0.0/20 permit 74.125.0.0/16 permit 64.18.0.0/20 permit 207.126.144.0/20 permit 173.194.0.0/16 permit 2001:4860:4000::/36 permit 2404:6800:4000::/36 permit 2607:f8b0:4000::/36 permit 2800:3f0:4000::/36 permit 2a00:1450:4000::/36 permit 2c0f:fb50:4000::/36 permit I tested the script under OpenBSD 5.3, FreeBSD 9.1, and Debian GNU/Linux 6.0.6. Comments are welcome.
