Good day,

I have come across an issue where client Mikrotiks are unable to renew their DHCPv6 PD binding if their binding was removed/deleted on the server side (Could be removed due to idle timeout on the PPPoE etc, Note: server is not a Mikrotik).

Setup: NDRA with DHCPv6 Prefix Delegation over PPPoE
Testing on Mikrotik Version: 7.12.1

If the client Mikrotik displays a bound prefix but the server does not have it, and the client initiates a renew, the server replys with Status Code: NoBinding (3). In such a scenario, shouldn't the client Mikrotik restart the DHCPv6 process and send a Solicit message (as outlined in RFC3633)? Not sure if there may be some extra configuration required or a bug.

Additionally, there are no issues if the client Mikrotik send a renew when there is still an active binding etc.

Attached screenshot of PCAP NoBinding (3) message.

Example Client Config:

/ipv6 settings
set accept-router-advertisements=yes max-neighbor-entries=8192
/ipv6 dhcp-client
add interface=pppoe-IPv6 pool-name=PD_POOL rapid-commit=no request=prefix
/ipv6 firewall filter
add action=accept chain=forward in-interface=bridge
add action=accept chain=forward connection-state=established,related in-interface=pppoe-IPv6
add action=accept chain=input in-interface=pppoe-IPv6 protocol=icmpv6
add action=accept chain=input comment=PD in-interface=pppoe-IPv6 protocol=udp src-address=fe80::/10 src-port=547
add action=drop chain=forward in-interface=all-ppp
add action=drop chain=input in-interface=all-ppp