AWS issues with 172.0.0.0/12

Thu Oct 3 21:53:34 UTC 2019

Auto generated VPC in AWS use RFC1819 addresses. This should not interfere
with pub up space.

What is the exact issue? If you can't ping something in AWS chances are
it's a security group blocking you.

On Tue, Oct 1, 2019, 7:00 PM Jim Popovitch via NANOG <nanog at nanog.org>
wrote:

> On October 1, 2019 9:39:03 PM UTC, Matt Palmer <mpalmer at hezmatt.org>
> wrote:
> >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.
> >
>
> I don't know their entire operations, but they do use some 172.16.0.0/12
> addresses internally. And yes, that is very different than 172/12, sorry
> for the confusion.
>
> -Jim P.
>
>
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