System information

Troubleshooting TCP/IP 7-115
TCP/IP: Poor Performance
TCP/IP: Poor Performance
Symptom: Performance for one or more network hosts is slow. Connections to servers take an
excessive amount of time to establish.
Table 7-8 outlines the problems that might cause this symptom and describes solutions to those
problems.
Table 7-8 TCP/IP: Poor Performance
Possible Problem Solution
Misconfigured resolv.conf
file on DNS client
Check the /etc/resolv.conf file on DNS clients. If the file is misconfigured, the
client might wait until a query to one server times out before trying a second
server, an NIS
1
, or its host tables. This can cause excessive delays.
1 NIS = Network Information Service
DNS is not set up for
reverse lookups
If the DNS server is not configured to perform reverse lookups, reverse lookup
attempts by end systems will time out. This can cause excessive delays for hosts
attempting to establish connections.
Consult your DNS software documentation for information on how to properly
configure the DNS for reverse lookups.
DNS host table is
incomplete
If the DNS host table is incomplete, reverse lookups will be unsuccessful, causing
timeouts and therefore delays.
Step 1 At the UNIX prompt, enter the following command:
unix-host% host ip-address
where ip-address is the IP address of a server, router, or other network
node.
Step 2 If the result of this command is Host not found, but you can open the
connection using the host’s IP address rather than its name, then the host
table might be incomplete.
Add address-to-hostname mappings to the DNS host table for every host
on the network.