Troubleshooting Tip: Avoiding IP Conflicts Between VRRP Virtual IP and VLAN Interface IP

dwivedis · ‎09-24-2024

Description

This article describes that the same IP address cannot be assigned to both the VRRP Virtual IP (VRIP) and the VLAN interface IP.

Scope

FortiSwitch.

Solution

This conflict often arises when the system interface's IP address and the VRRP virtual IP address are identical.

config system interface

edit "interface_name"

set mode static

set dhcp-relay-service disable

set ip 172.31.8.25 255.255.255.0

set allowaccess ping https http ssh telnet

set bfd disable

set bfd-desired-min-tx 250

set bfd-detect-mult 3

set bfd-required-min-rx 250

set icmp-redirect enable

set src-check disable

set status up

set type vlan

set description ''

set alias ''

set vrrp-virtual-mac enable

config vrrp

edit 1

set adv-interval 1

set backup-vmac-fwd enable

set preempt enable

set priority 50

set start-time 3

set status enable

set version 2

set vrdst 0.0.0.0 0.0.0.0

set vrgrp 10

set vrip 172.31.8.25

For the above configurations, the logs will be as below:

YYYY-MM-DD HH:MM:SS log_id=0103035000 tz=+0700 type=event subtype=system pri=notice vd=root user="ipconflictd" msg="IP Conflict: conflict detected on system interface LAN for IP address 172.31.8.25"

To resolve the conflict, configure a unique VRRP virtual IP:

config system interface

edit "interface_name"

set vrrp-virtual-mac enable

config vrrp

edit 1

set vrip 172.31.8.28 # Replace with a unique IP address

Note:

Ensure that the new VRRP virtual IP is within the same subnet as the system interface's IP address.

Verification:

After making the changes, check the FortiSwitch's logs to confirm that the IP conflict has been resolved.

Troubleshooting Tip: Avoiding IP Conflicts Between VRRP Virtual IP and VLAN Interface IP

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