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PBX port registration and usage

Article: 100021789
Dernière publication: 2014-10-15
Evaluations: 1 1
Produit(s): NetBackup & Alta Data Protection

Problem

What TCP ports are used by PBX and need to be available.

Solution

Background
The Veritas (formerly Veritas) PBX service (pbx_exchange) is a listener service that transfers inbound connections to local processes that have previously registered with PBX to receive connections.  This allows multiple client and server processes to connect between hosts without needing to have more than one TCP port open through network firewalls.

PBX uses the following TCP ports.
  • 1556 : Used to listen for inbound connections from remote hosts via any local network interface.  This port number is registered with IANA and should not be used by any non-Veritas applications and should not be changed.
  • 1557 : Was historically used by PBX to accept, from the local loopback interface only, connections from local processes on behalf of which it was listening.  It is no longer used by NetBackup 7.0 and newer versions.
  • A random port : Is now used by registered local processes to maintain connectivity to PBX and receive the transfer of new inbound connections from remote hosts.  As with 1557, PBX listens on this port only for the local loopback interface.
Like all application services, PBX will attempt to bind and listen on its well-known port upon startup.  If it cannot, it will not start.  Likewise if it cannot bind 1557 or a random port for communication with local processes it also will not start.
Note: Services that must bind to specific TCP ports should be started before other processes that create connections using random source ports in the same range.  Adjust the service startup order as necessary.
Note: The NetBackup Client Port Window does not constrain the PBX random port selection because PBX is generic service available to NetBackup and non-NetBackup services and clients alike.  See related articles.
 
Troubleshooting
A) (UNIX) Ensure that the operating system (OS) has one or more plumbed network interfaces including a loopback interface.
$ ifconfig -a
 
B) Ensure that PBX can identify and resolve the loopback interface and hostname.  If it cannot, PBX may not start, or may not be able to accept registrations from local processes, and therefore cannot not accept and then transfer inbound connections to the local processes.
1) Verify that 'localhost' resolves correctly to a loopback interface that is plumbed.
$ bpclntcmd -hn localhost
2) If not, correct name services.
This may involve adding or correct the 'localhost' entry in the hosts file; /etc/hosts (UNIX), %SystemRoot%\System32\drivers\etc\hosts (Windows).
On UNIX, be sure that the /etc/nsswitch.conf is configured to allow the 'files' source to be used to resolve 'hosts' database lookups before DNS or other name services.
 
C) Ping the localhost from a terminal or console session on the PBX host, troubleshoot any associated OS problem.
 
D) Ping and/or traceroute from the remote host to the PBX host, alternatively 'telnet <pbx_host> 1556', troubleshoot any network routing for firewall issues.
 
In this case, the loopback interface (lo0) was incorrectly bound to a different IP address; i.e. not 127.0.0.1.

 


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