Browser is one way how normal user interact with the web. However, it is not the only way (User-Agent). Another way is using curl command. Here are some common options:
curl -X POST -d "username=user&password=user&submit=Login" http://MACHINE_IP/post.phpcurl -c cookies.txt -d "username=admin&password=admin" http://MACHINE_IP/session.phpcurl -b cookies.txt http://MACHINE_IP/session.phpcurl -A "internalcomputer" http://MACHINE_IP/ua_check.php