brctl showstp shows ports that are admin up/carrier down as blocking:
[email protected]$ sudo brctl show bridge bridge name bridge id STP enabled interfaces bridge 8000.c45444bcfc8a yes swp1
[email protected]$ ip l sh swp1 28: swp1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast master bridge state DOWN mode DEFAULT qlen 500 link/ether c4:54:44:bc:fc:8a brd ff:ff:ff:ff:ff:ff
[email protected]$ sudo brctl showstp bridge ... swp1 (1) port id 8001 state blocking ...
- Cumulus Linux, all versions
mstpctl showportdetail BRIDGE PORT, which more accurately reflects the port state as Disabled/discarding.
[email protected]$ sudo mstpctl showportdetail bridge swp1 bridge:swp1 CIST info enabled no role Disabled port id 8.001 state discarding ...