Question
How is the local network interface mapping determined for Floating IPs?
I am using a Floating IP (45.55.x.x
) as a secondary IP for a droplet (which has a default IP, 157.230.x.x
). When I look at the network interfaces on the droplet using ip -a
, I see the following:
momo@droplet:~$ ip a | head -n 20
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether [...] brd ff:ff:ff:ff:ff:ff
inet 157.230.x.x/20 brd 157.230.x.x scope global eth0
valid_lft forever preferred_lft forever
inet 10.10.0.5/16 brd 10.10.255.255 scope global eth0
valid_lft forever preferred_lft forever
inet6 [...]/64 scope link
valid_lft forever preferred_lft forever
After some testing using nginx, I can see that requests going through the floating IP are mapped to the second inet in the eth0 interface, 10.10.0.5
. My question is, how is that local IP address determined and mapped from the external IP (45.55.x.x
)?
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