AWS issues with 172.0.0.0/12

Tue Oct 1 21:39:03 UTC 2019

On Tue, Oct 01, 2019 at 04:50:33AM -0400, Jim Popovitch via NANOG wrote:
> On 10/1/2019 4:09 AM, Christopher Morrow wrote:
> > possible that this is various AWS customers making iptables/firewall mistakes?
> >    "block that pesky rfc1918 172/12 space!!"
> 
> AWS also uses some 172/12 space on their internal network (e.g. the network
> that sits between EC2 instances and the AWS external firewalls)

Does AWS use 172.0.0.0/12 internally, or 172.16.0.0/12?  They're different
things, after all.

- Matt