When you point your browser to your P4Web in Standard mode, you'll be prompted for a username and password.
If you are using P4Web in Viewer mode, you are not typically required to enter a password when you start P4Web. However, your Perforce administrator may have set up the P4Web Viewer at your site to require one.
At the browser's username/password prompt, you must enter the username that matches the one P4Web was started up with. Normally, this is the same as your system login or account username. If you do not know your Perforce username, you can go to the command-line and use the p4 set command to view the value of P4USER.
Each instance of P4Web (Standard mode) is available for use by one and only one user, although that user can make several browser connections to it at once.
If your Perforce username has no password associated with it -- which is likely to be the case if you're using Perforce for the first time -- it doesn't matter what you type in your browser's password prompt. However, you should edit your user spec immediately once you are connected with P4Web (Standard mode) to create a Perforce password for your username. The password you create this way is stored by the Perforce server.
A Perforce password prevents others users from using your P4Web, as well as your other Perforce client programs (P4Win, command line, etc.) If your username doesn't have a Perforce password, anyone can connect their browser to your P4Web (or any other Perforce client programs) and run commands that view and write files in your workspace.
Once you've created a Perforce password by editing your user spec, use that password in your browser's username/password prompt. If you enter the wrong password in the prompt, you'll see a Perforce password error message displayed in your browser. The message contains a link you can click on to redisplay the username/password prompt.
Your browser will continue to use the same password every time it communicates with P4Web. If you change your Perforce password, either by editing your user spec in P4Web, or with another Perforce client program, you'll get Perforce password errors in subsequent P4Web operations. Just click on the link in the error message to redisplay the browser username/password prompt and enter your new password.
Perforce passwords set in the environment on Windows and Unix are ignored by P4Web. This includes values set in the registry, shell variables, configuration variables, and values passed with the -P flag on the p4web startup command. (See How to Use P4Web for information about the p4web startup command.) You must enter your Perforce password at your browser's prompt to begin using P4Web.
If the p4web program is started up in an environment with a P4CONFIG value set, it will read Perforce configuration parameters -- including client name, user name, and Perforce Server port address -- from the file indicated by P4CONFIG. Furthermore, it will reread the file every time it receives a request from a your browser. If you modify your P4CONFIG file while P4Web is running, you will affect your P4Web's default configuration parameters. (P4CONFIG is supported on Unix and Windows. It is discussed in more detail in the Perforce User's Guide and the Perforce Command Reference found on the Perforce Documentation website.)