Cisco Cisco Email Security Appliance C390 사용자 가이드
Chapter 6 Managing and Monitoring via the CLI
Monitoring Via the CLI
6-256
Cisco IronPort AsyncOS 7.3 for Email Daily Management Guide
OL-23080-01
Checking the DNS Status
The
dnsstatus
command returns a counter displaying statistics of DNS lookup
and cache information. For each counter, you can view the total number of events
since the counter was last reset, since the last system reboot, and over the lifetime
of the system.
since the counter was last reset, since the last system reboot, and over the lifetime
of the system.
lists the available counters.
Table 6-10
Data in the dnsstatus Command
Statistic
Description
DNS Requests
A top-level, non-recursive request to the system DNS cache
to resolve a domain name.
to resolve a domain name.
Network
Requests
Requests
A request to the network (non-local) to retrieve DNS
information.
information.
Cache Hits
A request to the DNS cache where the record was found and
returned.
returned.
Cache Misses
A request to the DNS cache where the record was not found.
Cache
Exceptions
Exceptions
A request to the DNS cache where the record was found but
the domain was unknown.
the domain was unknown.
Cache Expired
A request to the DNS cache where the record was found
in the cache, considered for use, and discarded because it was
too old.
too old.
Many entries can exist in the cache even though their time to
live (TTL) has been exceeded. As long as these entries are not
used, they will not be included in the expires counter. When
the cache is flushed, both valid and invalid (too old) entries
are deleted. A flush operation does not change the expires
counter.
live (TTL) has been exceeded. As long as these entries are not
used, they will not be included in the expires counter. When
the cache is flushed, both valid and invalid (too old) entries
are deleted. A flush operation does not change the expires
counter.