Debugging Dns Client Activity - HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual

Domain Name System (DNS) Services
Troubleshooting DNS
12-14

Debugging DNS Client Activity

DNS client activity deals only with the DNS requests the router makes on its
own behalf. (The router always checks its own host table first. If it finds a
match, no debug messages appear.)
To monitor DNS client messages, move to the enable mode context and enter:
ProCurve# debug ip dns-client
Real-time debug messages tracking the ProCurve Secure Router's DNS client
activity will display. For example, if you try to ping a hostname that the
ProCurve Secure Router cannot find in its hostname table, the following
message appears:
DNS: CLIENT Transmitting query packet for <hostname>
If this message does not appear, then you have not specified an IP address for
the external server and should do so. (See "Specifying DNS Server Addresses"
on page 12-10.)
The command line interface (CLI) should next display this message:
DNS: CLIENT Received query response
If you do not receive this message, the external DNS server cannot resolve the
hostname. It is possible that the hostname is not valid. It is also possible that
the DNS server address has been miskeyed and is not that of a valid name
server. Find the address the router is contacting in the running-config (enter
show running-config and look for ip name-server <A.B.C.D>).
Before deleting the address and entering a new one, ping the server and verify
that the router can reach it. If the server does not reply, the server may be
down or the router's connection to the server may be down. The Stat LED for
the interface through which the router reaches the DNS server should be
green. See Chapter 3: Configuring Ethernet Interfaces, Chapter 4: Config-
uring E1 and T1 Interfaces, Chapter 5: Configuring Serial Interfaces for
E1- and T1-Carrier Lines, Chapter 6: Configuring the Data Link Layer
Protocol for E1, T1, and Serial Interfaces, and Chapter 7: ADSL WAN Con-
nections for tips on troubleshooting a connection.
Also verify that the route table includes a route to the server's subnet. See
Chapter 11: IP Routing—Configuring Static Routes for more information
about the route table.