HP-UX Secure Shell Getting Started Guide HP-UX 11i v1, HP-UX 11i v2, and HP-UX 11i v3 (5900-3142, June 2013)

7 Troubleshooting HP-UX Secure Shell
This chapter discusses methods to troubleshoot problems with HP-UX Secure Shell connections.
This chapter addresses the following topics:
• “Overview” (page 55)
• “Debugging the HP-UX Secure Shell Server” (page 55)
• “Debugging the HP-UX Secure Shell Client” (page 57)
• “Interpreting the Debug Output” (page 58)
• “Generating Debug Messages Using the LogLevel Configuration Directive” (page 60)
• “Logging Error and Debug Messages” (page 60)
• “Authentication Problems” (page 61)
• “Reporting Problems” (page 61)
Overview
HP-UX Secure Shell servers and clients provide built-in debugging. When an HP-UX Secure Shell
client tries to establish a connection with an HP-UX Secure Shell server, the HP-UX Secure Shell
server presents a list of authentication methods that it supports. If the HP-UX Secure Shell client fails
to authenticate itself using one method, it can try the next authentication method on the list. HP-UX
Secure Shell server attempts all supported authentication methods before declining the connection
request from the client.
When you experience a problem during a HP-UX Secure Shell connection, first run the HP-UX
Secure Shell client and server in debug mode. By default, debugging is not enabled on either the
HP-UX Secure Shell server or the HP-UX Secure Shell client. When invoked with appropriate
debugging command-line options, HP-UX Secure Shell server and client display messages about
their progress and failures. You can analyze these messages to identify problems. You can increase
the level of detail displayed in the debug output to obtain more information about the problem.
You can use either command-line options or the configuration directive on the HP-UX Secure Shell
server and client to control the debugging message level.
Depending on how debugging is configured, HP-UX Secure Shell logs error messages to the console
or to the /var/adm/syslog/syslog.log file.
Apart from the debugging options, the HP-UX Secure Shell Frequently Asked Questions (FAQ)
available at the following URL can help you solve some common problems:
nl
http://www.hp.com/go/hpux-security-docs
Debugging the HP-UX Secure Shell Server
The HP-UX Secure Shell server logs debug and error messages in the /var/adm/syslog/
syslog.log file. You can also configure the HP-UX Secure Shell server to log the messages in a
different file.
Debugging Options
The HP-UX Secure Shell server daemon, sshd, provides the following debugging options:
-d Specifies debug mode. The server sends verbose debug output to the system log and
does not put itself in the background. The server does not fork and processes only
one connection at a time. This option is intended only for debugging the server.
Overview 55