@nico I'm sorry but this is just wrong and I can prove it

from my desktop:

> ping 15.204.35.21
PING 15.204.35.21 (15.204.35.21): 56 data bytes
64 bytes from 15.204.35.21: icmp_seq=0 ttl=63 time=0.266 ms

Where is 15.204.35.21?

It goes to my default gateway / firewall.

But that IP isn't on any interfaces there

Instead there's a route that says:

# netstat -rn | grep 15.204
15.204.35.21 10.27.2.5 UGH1 bridge4

send that IP address to my FreeBSD jail at 10.27.2.5 (never mind that this route is actually installed on my firewall with iBGP from inside that jail)

and in that jail is where the IP address can be found on an interface

e0b_web: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500
options=8<VLAN_MTU>
ether 0e:40:b2:db:80:58
hwaddr 02:82:d7:33:3e:0b
inet 10.27.2.5 netmask 0xffffff00 broadcast 10.27.2.255
inet 15.204.35.21 netmask 0xffffffff broadcast 15.204.35.21
inet6 fe80::c40:b2ff:fedb:8058%e0b_web prefixlen 64 scopeid 0x58
groups: epair
media: Ethernet 10Gbase-T (10Gbase-T <full-duplex>)
status: active
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>



Routing does not work the way you think it does