The IP and DNS addresses are automatically retrieved and there's usually no need to configure them separately. If the addresses must be manually configured, you can do it in the following way:
- Select Settings > Connectivity > Settings > Network destinations > Internet.
- Select the access point which you want to configure.
- Select Options > Advanced settings > IPv4 settings.
- Define Phone IP address and DNS addresses. In DNS settings you can define both Primary and Secondary DNS addresses.