Re: Source IPv4 address selection vs BGP IX connection

From: Gregory Shapiro <gshapiro_at_freebsd.org>
Date: Wed, 24 Apr 2024 18:00:57 UTC
> The mistake your making, IMHO, is that an IX connected eBGP FreeBSD
> router _SHOULD NOT_ be doing ANYTHING other than BGP on the IX
> connected interface, and anything like DNS and outbound SMTP should be
> going inward on the AS, not outward to the internet.

Fair point and thank you for the advice.  I am locking it down to an
extent (denying all inbound ports except 22, 179 from an ipfw table list
of trusted hosts/peers/upstreams/downstreams) but not as tightly as you
suggest as I do use some on-Internet services.  Specifically, port 25 to
my own mail server (not unwashed Internet service, but sitting off of a
different network) for system generated mail (cron, /etc/periodic/ script
output), 53 to admittedly "unwashed" Google DNS, and 123 to
FreeBSD's NTP pool (again "unwashed" to an extent).

I will look at using local instances for the latter two.

I still see value in source IP selection, even outside of the IX use
case.