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Usage guidelines
When the notification function is enabled, the device can send notifications to the destination host. To
specify the notification type (inform or trap) and target host, use the
snmp-agent target-host
command.
Examples
# Generate notifications as defined in RFC 2787 when the device in a VRRP group receives a VRRP
advertisement with the authentication type or key not matching the local configuration.
<Sysname> system-view
[Sysname] snmp-agent trap enable vrrp auth-failure
vrrp check-ttl enable
Use
vrrp check-ttl enable
to enable TTL check for IPv4 VRRP packets.
Use
undo vrrp check-ttl enable
to disable TTL check for IPv4 VRRP packets.
Syntax
vrrp check-ttl enable
undo vrrp check-ttl enable
Default
TTL check for IPv4 VRRP packets is enabled.
Views
Interface view
Predefined user roles
network-admin
mdc-admin
Usage guidelines
The master in an IPv4 VRRP group periodically sends VRRP advertisements to declare its presence.
The VRRP advertisements are multicast in the local subnet and cannot be forwarded by routers, so
the TTL value is not changed. When the master sends VRRP advertisements, it sets the TTL value to
255. If you enable TTL check, the backups drop the VRRP advertisements with TTL other than 255,
preventing attacks from other subnets.
Devices from different vendors might implement VRRP differently. When the device is interoperating
with devices of other vendors, TTL check on VRRP packets might result in unexpected dropping of
packets. In this scenario, use the
undo
vrrp
check-ttl
enable
command to disable TTL check on
VRRP packets.
Examples
# Disable TTL check for IPv4 VRRP packets.
<Sysname> system-view
[Sysname] interface vlan-interface 2
[Sysname-Vlan-interface2] undo vrrp check-ttl enable
vrrp dscp
Use
vrrp dscp
to configure a DSCP value for VRRP packets.
Use
undo vrrp dscp
to restore the default.