Chapter 4 Solving Problems with Your Solstice PPP Client

This chapter tells you how to detect and resolve problems with Solstice PPP installed on a client machine.

• "First Steps in Troubleshooting"

• "Understanding the Log File"

• "Solving Common Problems"

First Steps in Troubleshooting

1. Check the cable between your machine and the modem, and the cable between the modem and the telephone socket.

2. Check that the modem is switched on, and is configured correctly.

3. Check that you ran pppinit correctly, and that you entered the configuration information exactly as it was given to you.

4. Check that Solstice PPP is configured and running on your machine, by typing:

prompt% ps -ef | grep ppp
root pid timestamp 0:00 /usr/sbin/pppd -d 1
root pid timestamp 0:00 /usr/sbin/pppd -d 1

1. Check for error and status messages in the Solstice PPP log file (/var/opt/SUNWconn/ppp.log), by typing:

prompt# tail -f /var/opt/SUNWconn/ppp.log
05/31/95 22:52:48 - Link manager (17302) has started 05/31/95
05/31/95 22:52:48 - Successful configuration
05/31/95 22:55:02 - Connection requested to remote_server
05/31/95 22:55:03 - Dialing number 389 ...
05/31/95 22:55:21 - Got modem connection
05/31/95 22:56:02 - fail at line 12 in chat script chat_script

Understanding the Log File

Error and status messages for Solstice PPP are written to the log file /var/opt/SUNWconn/ppp.log. These messages show the progress of successful connection attempts, and can help identify which part of your configuration may be causing a problem if the connection attempt fails.

To display the latest messages written to the log file, type:

prompt# tail -f /var/opt/SUNWconn/ppp.log

The following log file extract shows Solstice PPP started and configured successfully on your machine. A connection to a remote server is opened and then closed.

11/13/95 18:00:48 - Link manager (359) has started 11/13/95
11/13/95 18:00:48 - Successful configuration
11/13/95 18:00:58 - Connection requested to miles
11/13/95 18:00:59 - Dialing number P365 ...
11/13/95 18:01:32 - Got modem connection
11/13/95 18:01:35 - LCP up on ipdptp0
11/13/95 18:01:35 - IP_NCP up on ipdptp0
11/13/95 18:01:35 - IP up on interface ipdptp0, with timeout set
to 240 seconds
11/13/95 18:01:54 - Disconnect indication on ipdptp0
11/13/95 18:01:54 - IP_NCP down on ipdptp0
11/13/95 18:01:54 - LCP down on ipdptp0

Problems Configuring Solstice PPP

When Solstice PPP is started on your machine, it reads the configuration files that you created using the configuration script pppinit. If these files do not exist on your machine, Solstice PPP displays the following message:

starting ppp (not configured)

The following log file extract shows the error messages that are generated when one of the configuration files contains an error:

11/13/95 18:53:22 - Link manager (460) has started 11/13/95
11/13/95 18:53:22 - parse_config_file: unrecognized symbol
inactivity_timeout
11/13/95 18:53:22 - parse_config_file: unrecognized symbol 180
11/13/95 18:53:22 parse_config_file: Errors in configuration file
/etc/opt/SUNWconn/ppp/ppp.conf

In this example, there is an unrecognized keyword contained in the file ppp.conf, which is rejected when the file is parsed. If you have a problem in one of your configuration files, run the configuration script pppinit to regenerate it. Contact your system administrator or Internet provider for help, if this does not solve your problem.

Problems Getting the Modem Connection

The first step in the connection phase is the modem connection. The client dials the telephone number of the modem connected to the server, and the two modems communicate to set up the connection.

The following log file extract shows a failed attempt to establish the modem connection:

11/13/95 19:57:44 - Connection requested to miles
11/13/95 19:57:45 - Dialing number P365 ...
11/13/95 19:58:09 - remote host is busy

The message "remote host is busy" is displayed whenever the client receives a busy signal from the server. This may mean that the server modem is already in use by another client, or it may mean that there is a problem with the equipment. In this example, the error was provoked by using tone dialing with an office exchange that expected the client to use pulse dialing.

Try telephoning the number directly to make sure that you can reach the modem. If you cannot reach the modem, check the telephone number you are dialing. If you are sure that you are dialing the correct number, but you receive a busy signal systematically, contact your system administrator or Internet provider for help.

Problems with PPP Negotiation

Once you have a modem connection, the next step in the connection phase is the PPP negotiation. The client and the server communicate to negotiate a common configuration for the PPP link. The policy is to converge if at all possible; however, failure to agree on certain mandatory parameters will cause the negotiation to fail.

The following log file extract was generated when the PPP negotiation failed:

11/13/95 20:34:42 - Connection requested to miles
11/13/95 20:34:43 - Dialing number P365 ...
11/13/95 20:35:16 - Got modem connection
11/13/95 20:35:19 - LCP up on ipdptp0
11/13/95 20:35:19 - PPP error on ipdptp0: Negotiation of mandatory
options failed

In this example, the error was provoked by an IP address that did not match the IP address expected by the server. If the PPP negotiation fails, check your configuration against the information that your system administrator or Internet provider gave you. If it is correct, contact your system administrator or Internet provider for help, as they may need to modify the server configuration.

Problems with PAP and CHAP Authentication

PAP and CHAP authentication are used to prevent unauthorized clients from connecting to the server. If either of these authentication methods is enabled on the server, your system administrator or Internet provider will provide you with the relevant passwords and identifiers.

The following log file extract shows what happens when your client fails to respond to a request for authentication:

11/14/95 10:22:41 - Connection requested to miles
11/14/95 10:22:42 - Dialing number P365 ...
11/14/95 10:23:16 - Got modem connection
11/14/95 10:23:47 - PPP error on ipdptp0: Maximum number of
configure requests exceeded

In this example, the server requested PAP authentication and the client rejected the request. After a specified number of requests, the server broke the connection without starting the PPP negotiation.

The following log file extract shows what happens when the client responds to the request for authentication with the wrong password:

11/13/95 20:34:42 - Connection requested to miles
11/13/95 20:34:43 - Dialing number P365 ...
11/13/95 20:35:16 - Got modem connection
11/13/95 20:35:19 - LCP up on ipdptp0
11/13/95 20:35:19 - PPP error on ipdptp0: Negotiation of mandatory
options failed

In this example, the PPP negotiation fails and the server closes the connection automatically.

Problems with the Inactivity Timeout

The inactivity timeout closes the connection automatically when it remains unused for a specified number of seconds. This means that you do not pay for telephone connections that are left open accidently. However, if the inactivity timeout is too short, your connection may be closed prematurely.

The following log file extract shows an inactivity timeout triggered by the client after 60 seconds:

11/13/95 18:00:03 - IP up on interface ipdptp0, with timeout set
to 60 seconds
11/13/95 18:00:14 - Interface ipdptp0 has timed out

If the connection times out systematically, run the configuration script pppinit to regenerate the configuration files, and increase the inactivity timeout for calls to the server.

The following log file extract shows a connection that has been disconnected by the server for some reason. One possible cause is an inactivity timeout on the server that is shorter than the inactivity timeout on the client. Contact your system administrator or Internet provider for help if the server disconnects your client systematically.

11/13/95 18:13:46 - IP up on interface ipdptp0, with timeout set
to 240 seconds
11/13/95 18:15:47 - interface ipdptp0 has been disconnected

Solving Common Problems

The following sections describe common problems you may encounter when installing or using Solstice PPP.

Problems Installing Solstice PPP

Problem: Cannot start pkgadd(1M).

Solution: You must log in as root or become superuser before you can run the pkgadd.

Problem: Cannot find the packages for Solstice PPP.

Solution: Check that you typed the source directory correctly. If the Volume Manager (vold) is running on your machine, the Solstice PPP packages are located in /cdrom/ppp_3.0. If you are not running the Volume Manager (vold) on your machine, you need to mount the CD-ROM manually. See Solstice PPP 3.0.1 Installation Guide and Release Notes for detailed instructions.

Problems Using Solstice PPP

Problem: Solstice PPP stops working after upgrading to Solaris 2.5.

Solution: Solaris 2.5 creates a default file /etc/ttydefs, which overwrites some changes made by Solstice PPP. Safeguard the configuration files ppp.conf, ppp.link, and the CHAT scripts. Reinstall Solstice PPP to correct the problem.

Problem: Cannot establish PPP link. Operation fails with the status message: "PPP error on ip_interface: Maximum number of configure requests exceeded"

Solution: PPP Configure-request frames are generated to start the link establishment phase. After a certain number of frames (defined by the keyword lcp_max_restart in the file ppp.conf) are generated without a valid response, the client assumes that the remote server is unreachable. This may indicate one of the following:

• There is a problem with the physical connection between the two hosts. Check the cable to your modem.

• PPP is not running on the remote host. Check that PPP is configured and started at both ends of the link.

• The link establishment phase is not completed, because the configuration negotiation does not converge. Check for configuration problems.

• If you are trying to establish a link over a long-delay network, such as a satellite connection, or over a congested line, the maximum number of configure requests may be exceeded before the negotiation is completed. Increase the maximum number of configure requests sent (lcp_max_restart) and the time between retries (lcp_restart_timer).

  Problem: Cannot establish PPP link. Operation fails with the status message: "Authentication failed"

  Solution: The peer authentication phase failed. Check that the PAP and CHAP parameters set on the two hosts are coherent. If the server requests authentication using either PAP or CHAP, the client must participate in the authentication phase, or the link is closed.

  Problem: Cannot establish PPP link. Operation fails with the status message: "Loop back detected"

  Solution: The PPP frames generated by the remote server are being reflected. The magic numbers contained in the PPP frames indicate a loop back condition. This may indicate one of the following:

• There is a problem with the physical connection between the two hosts. Check the cable to your modem.

• The UNIX login sequence is not completed successfully. Check that the login id and password set in the CHAT script are correct, and that a corresponding user account exists on the remote server. Check that the rest of the login dialog defined in the CHAT script is correct. If the remote server is not running a Solaris environment, you may need to modify the login sequence provided in the template file created by pppinit(1M).

• The remote host fails to respond quickly enough, and the maximum number of configure requests is exceeded before the negotiation is completed. Increase the maximum number of configure requests sent (lcp_max_restart) and the time between retries (lcp_restart_timer).

  Problem: Modem dials unexpectedly, or when the machine is rebooted.

  Solution: The IP interfaces associated with Solstice PPP are usually marked down, by default. However, if you modify the file ppp.conf to mark the interfaces up, the PPP link manager initiates the PPP link automatically whenever an IP datagram is passed to the interface by the IP layer.

  Some applications and processes broadcast requests occasionally. For example, when searching for a license daemon, or when the machine is rebooted. The PPP link manager responds to the broadcast and tries to dial the remote host.

  To prevent this behavior, mark the relevant IP interface down, and use pppconn(1M) to initiate connections as required.

  Problem: The connection phase fails with the error message: "PPP error on ipdptp1: Negotiation of mandatory options failed"

  Solution: Check that the IP interface used to initiate the connection, and the IP interface associated with the dialup path used to accept the connection have coherent IP addresses. The source address on the client must match the destination address on the server.

  Problem: Cannot make rsh(1) or rlogin(1) connection to the remote host. Operation fails with the message "Permission denied"

  Solution: Check for the hostname, or IP address, of your local host in the files /etc/.rhosts and /etc/hosts.equiv on the remote host. A + character in these files enables access for all hosts.