Technical Tip: In FortiOS v7.6.6 and earlier, cannot configure IPv6 DHCP client when a BGP neighbour is configured

Description

This article describes a known issue that can prevent configuring FortiGate as an IPv6 DHCP client while BGP neighbors are configured.

Scope

FortiOS v7.6.1 and later.

Solution

The FortiGate can operate as a dual-stack DHCP client for both IPv4 and IPv6 addresses. However, if any BGP neighbor is already configured, starting from FortiOS version 7.6.1, an error may appear in both the GUI and CLI when attempting to configure the IPv6 DHCP client feature on a firewall interface.

Error in GUI:

Error in CLI:

Home # config system interface

Home (interface) # 
Home (interface) # edit x2

Home (x2) # config ipv6

Home (ipv6) # set ip6-mode dhcp

Home (ipv6) # end
This IPv6 address is used in router.bgp.neighbor.
Please delete the BGP neighbor there first.
object set operator error, -23 discard the setting
Command fail. Return code -23

 
Workaround:

On affected platforms, there is no workaround. The issue is not reported for all platforms.

Resolution:

The fix for this issue (ID 1238186) has already been included in:

• v7.6.7 (Resolved Issues).

• v8.0.0 (Resolved Issues).