NPM sets the header with $proxy_add_x_forwarded_for, which appends the
connecting address to whatever the client sent. The first hop is therefore
client-controlled and the last is the one NPM vouches for. Reading the
first hop would have let an outsider claim a LAN address with one header,
and admin_api.client_is_lan decides on it. Found while verifying the nginx
block removal; fixed before the block came out was relied on. Also
tightens login throttling, which used the same helper.
thethreemagi
c458b8e64d