The onslookup program
lets you query other name servers with the same query packet another
name server would use. This is helpful in diagnosing lookup problems
in TCP/IP UNIX System Services.
To turn debugging on at level 1, enter the following commands
from the
z/OS shell:
onslookup
set debug
The
onslookup program shows
timeouts and displays response packets.
To turn the debug option off, enter the following command:
set nodebug
You can set the debugging option to level 2 by entering
the set d2 command just as the set debug command
was entered previously. The set d2 command provides
program trace information and set debug shows parts
of the formatted DNS response message.
The resolver shows the normal debugging information plus
the query packets that were sent out. Turning on d2 also
turns on debug. Turning off d2,
however, turns off only d2; debug remains
on. To turn off both d2 and debug,
enter the command set nodebug.
If the lookup request was not successful, an
error message is printed. Possible errors include:
- Timed out
- The server did not respond to a request after a certain amount
of time (changed with set timeout=value)
and a certain number of retries (changed with set retry=value).
- No response from server
- No name server is running on the server machine.
- No records
- The server does not have resource records of the current query
type for the host, although the host name is valid. The query type
is specified with the set querytype command.
- Non-existent domain
- The host or domain name does not exist.
- Connection refused
- The host or domain name refused the connection.
- Network is unreachable
- The connection to the name could not be made at the current time.
This error commonly occurs with ls requests.
- Server failure
- The name server found an internal inconsistency in its database
and could not return a valid answer.
- Refused
- The name server refused to service the request.
- Format error
- The name server found that the request packet was not in the correct
format. It might indicate an error in nslookup.
Note: The onslookup messages are not
documented in the z/OS® Communications
Server library.
Therefore, onslookup command messages do not give
a message ID for debugging.
For help with onslookup commands from
the command line, type onslookup -h.