Modification Type:  Supplement

Modification:
The bpclntcmd binary (found in the <install_path>\veritas\netbackup\bin directory on a Windows server, and in the /usr/openv/netbackup/bin directory on a UNIX/Linux server) performs name resolution using the same system calls as the NetBackup software.  The -pn, -self, -hn, and -ip switches are useful in troubleshooting network connectivity issues associated with name resolution.  This technote outlines some of the system calls these options use, as well as recommended troubleshooting steps when errors are returned by the command.  

bpclntcmd -pn
When the -pn option is run on a NetBackup client, it initiates an inquiry to NetBackup master server, and the master server returns information about the requesting client to the requesting client.  The information returned is, in effect, how the master server "identifies" the client server.  The client contacts the first server listed in its servers list, found in the bp.conf file on UNIX/Linux clients (the SERVER= lines) and in the Backup, Archive, and Restore GUI, under File - Specify NetBackup Machines and Policy Type on a Windows client.  

Bpclntcmd identifies the server replying to the request (the "expecting response from" line), and then it displays the information returned from that server.  The following is an example of the output of the bpclntcmd -pn command:

C:\Program Files\VERITAS\NetBackup\bin>bpclntcmd -pn
expecting response from server master_server_01
client_01.domain.com client_01 192.168.0.30 3815

In the above example:
 

- The master server is "master_server_01"
 

- The connection name is "client_01.domain.com"
 

- The NetBackup client name is "client_01"
 

- The IP address of "client_01" is 192.168.0.30
 

- The port used to connect is 3815.  
 

In effect, the master server identifies the requesting client as a machine named "client_01" with an IP address of 192.168.0.30.  

If the output showed *NULL* for the NetBackup client name (as shown below), the client is not configured in a policy and does not show up in the image database.

C:\Program Files\VERITAS\NetBackup\bin>bpclntcmd -pn
expecting response from server master_server_01
client_01.domain.com *NULL* 192.168.0.30 3815

Review the policy configuration on the master server, and see if the computer name is listed correctly in the policy on the master server.  

Unlike the other switches for bpclntcmd, the -pn option is logged in the bprd log on the master when bprd tries to resolve the IP to a hostname.  This command can be very useful to troubleshoot multiple interfaces on a single client.  If this command is failing, check the bprd log on the master to see what IP address is being resolved.  Additionally, check the following:

 

- Check the permission on the services file (found in C:\WINDOWS\system32\drivers\etc on a Windows machine, and the /etc directory on a UNIX/Linux machine). If the bpclntcmd command is being run by a non-root/administrative user, ensure they have permission to read the services file.
 

- Ensure the entry in the services file for the bprd service is correct - if this is missing/commented out or the port number is incorrect, then this problem can occur.   (i.e:  bprd   13720/tcp    bprd)      
 

- For a UNIX/Linux machine, check the nsswitch.conf file.  This file is used to determine how the services file is resolved. Ensure the permissions here are correct as well.
 

- If NIS is being used, the services file on the NIS Master should be checked and pushed out to the NIS clients.
 

- Check the SERVER entries for discrepancies in the bp.conf file or in the servers list (on a Windows client).  For example, the master-server name is misspelled, with two dots: master..domain.com.  
 

Sample bprd log entry:

08:33:17.290 [1843254] <2> logconnections: BPRD ACCEPT FROM 192.168.0.30 3815 TO 192.168.0.1.13720
08:33:17.292 [1843254] <2> connected_peer: Connection from host client_01.domain.com, 192.168.0.30, on non-reserved port 3815
08:33:17.297 [1843254] <2> process_request: no authentication required
08:33:17.297 [1843254] <2> nb_is_valid_master_server: checking if client_01.domain.com is a valid server
08:33:17.298 [1843254] <2> nb_is_valid_master_server: *** host client_01.domain.com is NOT a valid server
08:33:17.298 [1843254] <2> nb_is_valid_master_server:     h_name is client_01.domain.com
08:33:17.298 [1843254] <2> nb_is_valid_master_server:     ip address is 192.168.0.30 (0x276e520a)
08:33:17.298 [1843254] <2> db_valid_master_server: client_01.domain.com is not a valid server
08:33:17.438 [1843254] <2> process_request: command C_CLIENT_ID (45) received
08:33:17.438 [1843254] <2> process_request: client_01.domain.com is 6.0MP_4
08:33:17.438 [1843254] <2> get_ccname: determine configured name for client_01.domain.com
08:33:17.441 [1843254] <2> getsockconnected: host=master_server_01.com service=bpdbm address=192.168.0.1 protocol=tcp non-reserved port=13721
08:33:17.442 [1843254] <2> bind_on_port_addr: bound to port 40151
08:33:17.442 [1843254] <2> logconnections: BPDBM CONNECT FROM 192.168.0.1.40151 TO 192.168.0.1.13721
08:33:17.444 [1843254] <2> check_authentication: no authentication required
08:33:19.042 [1843254] <2> get_ccname: configured name is: client_01.domain.com

bpclntcmd -self
The -self option reports information about the client without making any connection to the master server.  This is, in effect, how the client "identifies" itself.  

Sample output:
C:\Program Files\VERITAS\NetBackup\bin>bpclntcmd -self
gethostname() returned: client_01
host client_01: client_01.domain.com at 192.168.0.30 (0x276e520a)
checkhname: aliases:

In the above example, the NetBackup client name is client_01, the fully qualified domain name is client_01.domain.com, and its IP address is 192.168.0.30.  This information can be helpful when used in conjunction with the -pn output.  For example, if the -pn output indicated the NetBackup client name was client_01 with an IP address of 192.168.0.30 and the -self option returned client_01 with an IP address of 192.168.0.31, this would indicate incorrect information within the name resolution environment. The client and master server are resolving the client's name to two different IP addresses.  

bpclntcmd -ip <ip_address>
The -ip option requests the bpclntcmd binary resolve the given IP address to a name using the gethostbyaddr() system call on the NetBackup node.  It attempts to obtain the host name associated with the IP address as defined in the node's Domain Name Service (DNS), local hosts file, or Windows Internet Naming Service (WINS) entries.  Like the -self option, no connection is made to the master server.  

Sample output:
C:\Program Files\VERITAS\NetBackup\bin>bpclntcmd -ip 192.168.0.30
checkhaddr: host   : client_01: client_01.domain.com at 192.168.0.30
(0x276e520a)
checkhaddr: aliases:

bpclntcmd -hn <host_name>
The -hn option requests the bpclntcmd binary resolve the given host name to an IP address using the gethostbyname() system call on the NetBackup node.  It attempts to obtain the IP address associated with the host name as defined in the node's Domain Name Service (DNS), local hosts file, or Windows Internet Naming Service (WINS) entries.  Like the -self option, no connection is made to the master server.  

Sample output:
C:\Program Files\VERITAS\NetBackup\bin>bpclntcmd -hn client_01
host client_01: client_01.domain.com at 192.168.0.30 (0x276e520a)
checkhname: aliases:

On the NetBackup master server, use bpclntcmd -hn to confirm the operating system can resolve the host name of the NetBackup client (as configured in the client list for the policy) to an IP address. The IP address is then used in the node's routing tables to route a network message from the NetBackup server.

Note: The bpclntcmd command logs to the bplist debug log.