Configuring CHAP Authentication on the Dial-in Server
The first task in setting up CHAP authentication is modifying the /etc/ppp/chap-secrets file. This file contains the CHAP security credentials, including the CHAP secret, that are used to authenticate callers on the link.
Note - UNIX or PAM authentication mechanisms do not work with CHAP. For example, you cannot use the PPP login option as described in "How to Create a PAP Credentials Database (Dial-in Server)". If your authentication scenario requires PAM or UNIX-style authentication, choose PAP instead.
The next procedure implements CHAP authentication for a dial-in server in a private network. The PPP link is the only connection to the outside world. The only callers who are allowed to access the network are individuals who have been granted permission by managers of the network, possibly including the system administrator.
How to Create a CHAP Credentials Database (Dial-in Server)
Assemble a list that contains the user names of all trusted callers--people who have been granted permission to call the private network.
Assign each user a CHAP secret.
Note - Be sure to choose a good CHAP secret that is not easily guessed. No other restrictions are placed on the CHAP secret's contents.
The method for assigning CHAP secrets depends on your site's security policy. Either you have the responsibility for creating the secrets, or the callers must create their own secrets. If you are not responsible for CHAP secret assignment, be sure to get the CHAP secrets that were created by, or for, each trusted caller.
Become superuser on the dial-in server, and modify the /etc/ppp/chap-secrets file.
Solaris PPP 4.0 includes an /etc/ppp/chap-secrets file that contains helpful comments but no options. You can add the following options for the server CallServe at the end of the existing /etc/ppp/chap-secrets file.
account1 CallServe key123 * account2 CallServe key456 *
key123 is the CHAP secret for trusted caller account1. key456 is the CHAP secret for trusted caller account2.
Where to Go From Here
Task | For Instructions |
|---|---|
Create CHAP credentials for additional trusted callers | "How to Create a CHAP Credentials Database (Dial-in Server)" |
Update the PPP configuration files to support CHAP | "How to Add CHAP Support to the PPP Configuration Files (Dial-in Server)" |
Set up CHAP authentication on the dial-out machines of trusted callers | "Configuring CHAP Authentication for Trusted Callers (Dial-out Machines)" |
Modifying the PPP Configuration Files for CHAP (Dial-in Server)
The task in this section explains how to update existing PPP configuration files to support CHAP authentication on the dial-in server.
How to Add CHAP Support to the PPP Configuration Files (Dial-in Server)
Log in to the dial-in server as superuser.
Modify the /etc/ppp/options file.
Add the options that are shown in bold for CHAP support.
# vi /etc/ppp/options lock nodefaultroute name CallServe auth require-chap
Create the remaining PPP configuration files to support the trusted callers.
See "How to Configure Users of the Dial-in Server" and "How to Define Communications Over the Serial Line (Dial-in Server)".
Where to Go From Here
Task | For Instructions |
|---|---|
Configure CHAP authentication credentials for trusted callers | "How to Create a CHAP Credentials Database (Dial-in Server)" |
Configuring CHAP Authentication for Trusted Callers (Dial-out Machines)
This section contains tasks for setting up CHAP authentication on the dial-out machines of trusted callers. Depending on your site's security policy, either you or the trusted callers might be responsible for setting up CHAP authentication.
If remote callers are to configure CHAP, be sure that the callers' CHAP secrets correspond with the CHAP secrets that are listed for them in the dial-in server's /etc/ppp/chap-secrets file. Then give the callers the tasks in this section for configuring CHAP.
Configuring CHAP for trusted callers involves two tasks:
Creating the callers' CHAP security credentials
Configuring the callers' dial-out machines to support CHAP authentication
How to Configure CHAP Authentication Credentials for the Trusted Callers
This procedure shows how to set up CHAP credentials for two trusted callers. The steps in the procedure assume that you, the system administrator, are creating the CHAP credentials on the trusted callers' dial-out machines.
Become superuser on a dial-out machine.
Using the sample CHAP configuration that was introduced in "Example--Configuration Using CHAP Authentication", assume that the dial-out machine belongs to trusted caller account1.
Modify the chap-secrets database for caller account1.
Solaris PPP 4.0 includes an /etc/ppp/chap-secrets file that has helpful comments but no options. You can add the following options to this existing /etc/ppp/chap-secrets file.
# account1 CallServe key123 *
CallServe is the name for the peer that account1 is trying to reach. key123 is the CHAP secret to be used for links between account1 and CallServer.
Become superuser on another dial-out machine.
Assume that this machine belongs to caller account2.
Modify the /etc/ppp/chap-secrets database for caller account2.
# account2 CallServe key456 *
Now account2 has secret key456 as its CHAP credentials for use over links to peer CallServe.
Where to Go From Here
Task | For Instructions |
|---|---|
Create CHAP credentials on the dial-out machines of trusted callers | "How to Create a CHAP Credentials Database (Dial-in Server)" |
Configure a dial-out machine to support CHAP authentication | "How to Configure CHAP Authentication Credentials for the Trusted Callers" |
Adding CHAP to the Configuration Files (Dial-out Machine)
The next task configures the dial-out machine that belongs to caller account1, introduced in "Example--Configuration Using CHAP Authentication".
How to Add CHAP Support to the PPP Configuration Files (Dial-out Machine)
Log in to the dial-out machine as superuser.
Ensure that the /etc/ppp/options file has the following options.
# vi /etc/ppp/options lock nodefaultroute
Create an /etc/ppp/peers/peer-name file for the remote machine CallServe.
# mkdir /etc/ppp/peers # vi CallServe /dev/cua/a 57600 noipdefault defaultroute idle 120 user account1 connect "chat -U 'mypassword' -f /etc/ppp/mychat"
The option user account1 sets account1 as the CHAP user name to be given to CallServe. For a description of the other options in the previous file, see the similar /etc/ppp/peers/myserver file in "How to Define the Connection With an Individual Peer".