Veritas NetBackup™ Troubleshooting Guide

About troubleshooting networks and host names

In a configuration with multiple networks and clients with more than one host name, NetBackup administrators must configure the policy entries carefully. They must consider the network configuration (physical, host names and aliases, NIS/DNS, routing tables, and so on). If administrators want to direct backup and restore data across specific network paths, they especially need to consider these things.

For a backup, NetBackup connects to the host name as configured in the policy. The operating system's network code resolves this name and sends the connection across the network path that the system routing tables define. The bp.conf file is not a factor making this decision.

For restores from the client, the client connects to the master server. For example, on a UNIX computer, the master server is the first one named in the /usr/openv/netbackup/bp.conf file. On a Windows computer, the master server is specified on the Server to use for backups and restores drop-down of the Specify NetBackup Machines and Policy Type dialog box. To open this dialog, start the NetBackup Backup, Archive, and Restore interface and click Specify NetBackup Machines and Policy Type on the File menu. The client's network code that maps the server name to an IP address determines the network path to the server.

Upon receipt of the connection, the server determines the client's configured name from the peer name of its connection to the server.

The peer name is derived from the IP address of the connection. This means that the address must translate into a host name (using the gethostbyaddr() network routine). This name is visible in the bprd debug log when a connection is made as in the line:

Connection from host peername ipaddress ...

The client's configured name is then derived from the peer name by querying the bpdbm process on UNIX computers. On Windows computers, you must query the NetBackup Database Manager service.

The comparison is first a string comparison. The comparison is verified by comparing host names and the aliases that are retrieved by using the network function gethostbyname().

If none of the comparisons succeed, a more brute force method is used, which compares all names and aliases using gethostbyname().

The configured name is the first comparison that succeeds. Note that other comparisons might also have succeeded if aliases or other "network names" are configured.

If the comparison fails, the client's host name as returned by the gethostname() function on the client is used as the configured name. An example of a failed comparison: the client changes its host name but its new host name is not yet reflected in any policies.

These comparisons are recorded in the bpdbm debug log if VERBOSE is set. You can determine a client's configured name by using the bpclntcmd command on the client. For example:

# /usr/openv/netbackup/bin/bpclntcmd -pn (UNIX)

# install_path\NetBackup\bin\bpclntcmd -pn (Windows)

expecting response from server wind.abc.me.com 
danr.abc.me.com danr 194.133.172.3 4823

The browse client name is used to identify the client files to list or restore from. The user on the client can modify this name to restore files from another client. For example, on a Windows client, the user can change the client name by using the Backup, Archive, and Restore interface. (See the NetBackup online Help for instructions). For this change to work, however, the administrator must also have made a corresponding change on the server.

See the NetBackup Administrator's Guide, Volume I.

The requesting client is the value from the gethostname() function on the client.

The destination client name is a factor only if an administrator pushes a restore to a client from a server. For a user restore, the destination client and the requesting client are the same. For an administrator restore, the administrator can specify a different name for the destination client.

By the time these names appear in the bprd debug log, the requesting client name has been translated into the client's configured name.

The name that used to connect back to the client to complete the restore is either the client's peer name or its configured name. The type of restore request (for example, from root on a server, from a client, to a different client, and so on) influences this action.

Any of these client names can require manual modification by the administrator if the following: a client has multiple network connections to the server and restores from the client fail due to a connection-related problem.

On UNIX, the public domain program traceroute (not included with NetBackup) often can provide valuable information about a network's configuration. Some system vendors include this program with their systems. For Windows, use the tracert command.

The master server may be unable to reply to client requests, if the Domain Name Services (DNS) are used and the following is true: The name that the client obtains through its gethostname() library (UNIX) or gethostbyname() network (Windows) function is unknown to the DNS on the master server. The client and the server configurations can determine if this situation exists. gethostname() or gethostbyname()on the client may return an unqualified host name that the DNS on the master server cannot resolve.

Although you can reconfigure the client or the master server DNS hosts file, this solution is not always desirable. For this reason, NetBackup provides a special file on the master server. This file is as follows:

/usr/openv/netbackup/db/altnames/host.xlate (UNIX)

install_path\NetBackup\db\altnames\host.xlate (Windows)

You can create and edit this file to force the desired translation of NetBackup client host names.

Each line in the host.xlate file has three elements: a numeric key and two host names. Each line is left justified, and a space character separates each element of the line.

key hostname_from_client client_as_known_by_server

This following is an example:

0 danr danr.eng.aaa.com