This is a reproducible RouterOS v7 issue affecting IPv4 routing over ipipv6 interfaces.
Summary:
- IPv6 connectivity is working (AFTR reachable, ICMPv6 OK)
- ipipv6 interface is RUNNING
- IPv4 address can be assigned to ipipv6 interface
- RouterOS creates IPv4 connected route
- However, the route remains DIc and never becomes ACTIVE
- As a result, no IPv4 packets are generated
This occurs not only with DS-Lite (RFC6333) but also with a plain ipipv6 tunnel.
MikroTik support (SUP-209458) confirmed:
- This is not a configuration issue
- There is no user-configurable way to change this behavior
Impact:
This prevents RouterOS from functioning as a DS-Lite CPE on networks such as NTT FLET'S (Japan), where IPv4 connectivity depends entirely on IPv4-over-IPv6.
Required behavior:
RouterOS should allow IPv4 L3 routing over ipipv6 interfaces.
The IPv4 connected route should become ACTIVE when:
- interface is RUNNING
- IPv6 path is reachable
- IPv4 address is assigned
Question to MikroTik developers:
Is this a known limitation, or a defect to be fixed?