Cisco Catalyst 3550 Command Reference Manual page 539

Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
Defaults This command is disabled by default. No notifications are sent.
If you enter this command with no keywords, the default is to send all trap types to the host. No informs
are sent to this host.
If no version keyword is present, the default is version 1.
If version 3 is selected and no authentication keyword is entered, the default is the noauth
(noAuthNoPriv) security level.
Command Modes Global configuration
Command History Release
12.1(4)EA1
12.1(8)EA1
12.1(9)EA1
12.1(11)EA1
12.1(12c)EA1
12.1(13)EA1
12.1(14)EA1
12.2(25)SE
Usage Guidelines
SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver
does not send acknowledgments when it receives traps. The sender cannot determine if the traps were
received. However, an SNMP entity that receives an inform request acknowledges the message with an
SNMP response PDU. If the sender never receives the response, the inform request can be sent again.
Thus, informs are more likely to reach their intended destinations.
However, informs consume more resources in the agent and in the network. Unlike a trap, which is
discarded as soon as it is sent, an inform request must be held in memory until a response is received or
the request times out. Traps are also sent only once, but an inform might be retried several times. The
retries increase traffic and contribute to a higher overhead on the network.
If you do not enter an snmp-server host command, no notifications are sent. To configure the switch to
send SNMP notifications, you must enter at least one snmp-server host command. If you enter the
command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must
enter a separate snmp-server host command for each host. You can specify multiple notification types
in the command for each host.
If a local user is not associated with a remote host, the switch does not send informs for the auth
(authNoPriv) and the priv (authPriv) authentication levels.
When multiple snmp-server host commands are given for the same host and kind of notification (trap
or inform), each succeeding command overwrites the previous command. Only the last snmp-server
host command is in effect. For example, if you enter an snmp-server host inform command for a host
and then enter another snmp-server host inform command for the same host, the second command
replaces the first.
OL-8566-01
Modification
This command was introduced.
The mac-notification keyword was added.
The vlan-membership keyword was added.
The version 3 option was added, with the auth, noauth, and priv keywords.
The bgp keyword was added.
The envmon keyword was added.
The port-security keyword was added.
The bridge, copy-config, flash, stpx, syslog, vlancreate, and vlandelete
keywords were added.
The ipmulticast, msdp, ospf, pim, storm-control trap rate value, and vrf
vrf-instance keywords were added.
Catalyst 3550 Multilayer Switch Command Reference
snmp-server host
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