On 4/23/2024 10:12 PM, Gregory Shapiro wrote:
Short version:
Using FreeBSD as a BGP router has network issues caused by suboptimal
default IPv4 source address selection when connected to Internet
Exchanges (which are required to use IPs that aren't routable on the
Internet). I was hoping to find more elegant workarounds or encourage
FreeBSD to add source IPv4 selection akin to the existing IPv6 source
address selection (no_prefer_iface and prefer_source).
I assume that there is a group of BGP enthusiasts using FreeBSD lurking
on freebsd-net. What have you done to solve this problem?
For DNS in such situations I start unbound locally and bind it to an
internal interface or an IP on lo0 and then tell unbound to just use
that IP only (outgoing-interface IIRC) that is advertised out as a work
around. Its not a proper solution, but will get your resolver working
at least. I run into this problem in layered networks where the next hop
is often RFC 1918 addrs. I bind applications to internal NICs that have
addresses that have routing to/from.
---Mike
