On Thu, May 16, 2024 at 9:39 AM Mark Tinka via zanog-discuss zanog-discuss@lists.nog.net.za wrote:
On 5/15/24 22:00, Hendrik Visage via zanog-discuss wrote:
Anybody else being as masochistic as I am to attempt using FRR's IS-IS with unnumbered interfaces? It works "like a charm" with IPv6, but IPv4 isn't routed if no IPv4 IPs on the IS-IS connected interfaces. Using Openfabric (based on and in the isisd code), it all just works... correctly (So why am I not using Openfabric? as I want to use it with multi node links/networks which Openfabric doesn't support/do, and I'm interested in interfacing with other network kit, so IS-IS is the beterer choice as openfabric is "dead" in IETF, replaced by the dist-opt-flood extensions to IS-IS)
My experience with IS-IS is only on Cisco and Juniper, so can't say much about FRR. I tried to get IS-IS on FRR on FreeBSD going a few years ago, but that ended in tears, so I abandoned it.
IT (and especially networking?) is full of tears ;(
Unnumbered IS-IS interfaces will work for IPv6 because IPv6 always has a Link-Local address anyway.
Correct - yet another reason to switch to IPv6 only ASAP :)=)
In Cisco, unnumbered IS-IS interfaces work as long as the interface is in "point-to-point" mode. I see you have that mode in your configuration, so what it sounds like to me is that it is currently unsupported, or support is incomplete, on FRR.
I'm going with "support is incomplete" ... now to find the right places in the code to augment and give a pull request.... the bucketlist just grew by another lifetime
As a hack, can you try routing a static IPv4 address via your unnumbered interfaces, without a next-hop target? I know that was a hack to create ARP glue for unnumbered interfaces on Cisco back in the day.
Yes, at the bottom I did just that, added the loopback IPv4 to each interface and things worked (TM), but I guess I could, and will check that adding a Link-local 169.254.0.x IP should also work.... now to "automate" that... how do I add a link-local type IPv4 address without a DHCP client...