Hi,

In the \Symfony\Bridge\Monolog\Processor\WebProcessor class, the content of the server attributes of the request is copied info the serverData property.

When processing the request, \Monolog\Processor\WebProcessor computes some fields from the serverData (which is basically $_SERVER), such as REMOTE_ADDR for the ip field.
Sadly it is not matching the "correct" IP from Request->getClientIp() for instance.
It's a problem when symfony is used behind a load balancer

An easy fix would be to override the REMOTE_ADDR to Request->getClientIp() in the serverData. Not sure if clear but I can do a PR if needed.