In tutorial 0.7-PHP-Lambda-functions-with-Docker-container-images the created container does not have access to the network.
I did a simple try with gethostbyaddr:

$reverse = gethostbyaddr('51.255.200.41');
return APIResponse("Hello, ". $data['queryStringParameters']['name'] . " - $reverse");

When testing into the local container gethostbyaddr return the IP address, becuause it can't query DNS servers.
Pushing into AWS Lambda works fine.

It would be fine to adjust this tutorial explainig how to do it.