Single Sign-On (Sso); Introduction - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

This output shows the system is running portmap due to the presence of the sunrpc service.
However, there is also a mystery service on port 834. To check if the port is associated with the official
list of known services, type:
cat /etc/services | grep 834
This command returns no output. This indicates that while the port is in the reserved range (meaning 0
through 1023) and requires root access to open, it is not associated with a known service.
Next, check for information about the port using netstat or lsof. To check for port 834 using
netstat, use the following command:
netstat -anp | grep 834
The command returns the following output:
tcp 0 0 0.0.0.0:834
The presence of the open port in netstat is reassuring because a cracker opening a port
surreptitiously on a hacked system is not likely to allow it to be revealed through this command. Also,
the [p] option reveals the process ID (PID) of the service that opened the port. In this case, the open
port belongs to ypbind (NIS), which is an RPC service handled in conjunction with the portmap
service.
The lsof command reveals similar information to netstat since it is also capable of linking open
ports to services:
lsof -i | grep 834
The relevant portion of the output from this command follows:
ypbind 653
ypbind 655
ypbind 656
ypbind 657
These tools reveal a great deal about the status of the services running on a machine. These tools are
flexible and can provide a wealth of information about network services and configuration. Refer to the
man pages for lsof, netstat, nmap, and services for more information.

43.3. Single Sign-on (SSO)

43.3.1. Introduction

The Red Hat Enterprise Linux SSO functionality reduces the number of times Red Hat Enterprise
Linux desktop users have to enter their passwords. Several major applications leverage the same
0.0.0.0:* LISTEN
0 7u IPv4 1319
0 7u IPv4 1319
0 7u IPv4 1319
0 7u IPv4 1319
653/ypbind
TCP *:834 (LISTEN)
TCP *:834 (LISTEN)
TCP *:834 (LISTEN)
TCP *:834 (LISTEN)
Single Sign-on (SSO)
635