Server 2012, 2016: BGP does not resolve routes over teamed interfaces

see dat dere? 1 Reputation point
2020-07-30T23:37:53.047+00:00

Ran into this one while investigating BGP deployment for multi-homed servers to solve the static route mess.

  • BGP configured between Windows and [whatever: router, switch, etc]
  • Windows host receives routes with different next hops: some have the peer as next hop, some are via other subnets that the host lives in, so directly connected.
  • Everything works fine, routes get resolved and installed, get-netroute and ger-bgprouteinformation have them.

Problems start when either the peering interface or another interface involved in the next hops, is a teamed interface or a VLAN subinterface of a teamed interface:

  1. If BGP receives a route with next-hop via a teamed interface, route does not get installed
  2. If the peering is over a teamed interface, the peering itself will be up, but no routes via the peer will be installed
  3. If I set -DefaultGatewayRouting for BGP, the routes do get installed, obviously with the default GW as next hop, but this means that without this option, these routes are unresolved.
  4. Teamed interfaces also cannot be added to BGP to announce their prefixes. "Add-BgpCustomRoute -Interface [team name]" always comes back with "interface [team name] not found".

It basically seems as if teamed interfaces are "incompatible" with Windows' BGP - and teaming is the only way I know to enable VLAN tagging, and therefore there is no way to run BGP if teaming is involved.

Can someone in the know answer if this is a bug / missing feature or if there is some exotic property that needs to be enabled on teamed interfaces to play nicely with BGP? Does Server 2019 change this?

Just to pre-empt: I don't think there is any need to post details of my configuration, topology or vendors used. Reproducing this is trivial. Any BGP peering, any routes. Next hop via team = unresolved.

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