Compaq TCP/IP Services for OpenVMS
Tuning and Troubleshooting

Contents

Preface
Preface	Preface
Chapter 1
1	Troubleshooting Techniques and Tools
1.1	Using Symptoms to Identify a Problem
1.2	Isolating Problems
1.2.1	Testing Connectivity Between Network Hosts
1.2.1.1	Using ping on a Multihomed Host
1.2.2	Checking the Network Interface Parameters
1.2.3	Displaying and Modifying the Internet-to-Ethernet Translation Tables
1.2.4	Examining Network Statistics
1.2.5	Monitoring Network Traffic
1.2.6	Checking Name Server Operation
1.2.7	Checking the Route to a Remote Host
1.2.8	Checking the Routes Known to a Gateway
1.2.9	Determine Whether Network Services Are Available
1.2.9.1	Displaying the Service Database
1.2.9.2	Displaying Service Attributes
1.2.9.3	Verifying Process Privileges
1.2.9.4	Verifying Account Privileges
1.2.9.5	Looking for OPCOM Messages
Chapter 2
2	Tuning Techniques
2.1	Kernel Subsystems
2.1.1	Displaying Subsystems and Attributes
2.1.2	Testing Attribute Support
2.1.3	Displaying Attribute Values
2.1.4	Modifying Attribute Values
2.1.5	Modifying Attributes Temporarily
2.2	Modifying Kernel Subsystems
2.2.1	Modifying Socket Subsystem Attributes
2.2.1.1	Increasing the Maximum Number of Pending TCP Connections
2.2.1.2	Increasing the Minimum Number of Pending TCP Connections
2.2.1.3	Increasing the Maximum Size of a Socket Buffer
2.2.2	Modifying Internet Subsystem Attributes
2.2.2.1	Increasing the Size of a TCP Hash Table
2.2.2.2	Increasing the Number of TCP Hash Tables
2.2.2.3	Increasing the Size of the Kernel Interface Alias Table
2.2.2.4	Increasing the TCP Partial Connection Timeout Rate
2.2.2.5	Slowing TCP Retransmission Rate
2.2.2.6	Enabling the TCP Keepalive Function
2.2.2.7	Increasing the Timeout Rate for TCP Connection Context
2.2.2.8	Modifying the Range of Outgoing Connection Ports
2.2.2.9	Disabling Use of the PMTU Protocol
2.3	Monitoring Servers
2.3.1	Displaying Network Statistics
2.3.2	Displaying Socket Statistics
2.4	Tuning Server Applications
2.4.1	Configuring Memory for High Performance
2.4.2	Logging IP Addresses
2.5	Increasing the Auxiliary Server Connection Limit
2.6	Solving Performance Problems
2.6.1	Tuning Recommendations for a Primary Server
Appendix A
Appendix A	Troubleshooting Tools Reference
Command 1	arp
Command 2	dig
Command 3	ifconfig
Command 4	ndc
Command 5	netstat
Command 6	nslookup
Command 7	ping
Command 8	route
Command 9	sysconfig
Command 10	TCPTRACE
Command 11	traceroute
Appendix B
Appendix B	Commonly Used UNIX Commands
Index
Index
Tables
1	TCP/IP Services Documentation
1-1	Diagnostic Tools
2-1	Network Tuning Guidelines
2-2	socket Subsystem Attributes
2-3	inet Subsystem Attributes
2-4	TCP Keepalive Options
A-1	dig Options
A-2	Options to the nslookup set Command
B-1	Commonly Used Commands