How to register a Red hat Linux server in Red hat network ?

You need to make sure your server is able to talk to Red hat network thru internet.
For this, you need to add the proxy IP address (provided by your network team) on the file /etc/rhsm/rhsm.conf.

Add the details like proxy ip, port number, user name and password in the file rhsm.conf.

 # vi /etc/rhsm/rhsm.conf
proxy_hostname = x.x.x.x
proxy_port = 8080
proxy_user =
proxy_password =

You may need to add a user name and password for proxy connectivity.
However if the network admin adds your server IP address to the bypass list, then there may be no need to use user name and password for internet connectivity.

Finally you need to register (subscribe) your server in Red hat network.

2. Register the server in Redhat network.
# subscription-manager register --username --password --auto-attach
The system has been registered with id: 2a2334s3-3254-13e3-8r7e-2435324c5e45
Installed Product Current Status:
Product Name:           Red Hat Enterprise Linux Server
Status:                 Subscribed