I have been using the discard interface - DISC(4) - on FreeBSD for some time to tie down supernets. On frr7, I am getting a warning message at startup I am not sure what to make of The nic is configured as # ifconfig disc0 disc0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 65532         inet 10.128.128.144 netmask 0xfffffff8         inet 10.129.129.1 netmask 0xfffffff0         inet6 2001:db8::1 prefixlen 64         inet6 fe80::1%disc0 prefixlen 64 scopeid 0x7         groups: disc         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> And at startup, I get  /usr/local/etc/rc.d/frr start Checking zebra.conf 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface disc0 broadcast addr 10.128.128.144/29 != calculated 10.128.128.151, routing protocols may malfunction 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface disc0 broadcast addr 10.129.129.1/28 != calculated 10.129.129.15, routing protocols may malfunction 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309105] Disabling MPLS support (no kernel support) OK Starting zebra. 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface disc0 broadcast addr 10.128.128.144/29 != calculated 10.128.128.151, routing protocols may malfunction 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface disc0 broadcast addr 10.129.129.1/28 != calculated 10.129.129.15, routing protocols may malfunction 2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309105] Disabling MPLS support (no kernel support) If I use the same IP info on another non discard interface it works / doesnt complain. Also, when starting staticd, I get these warnings as well. Checking staticd.conf 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra 2019/04/26 15:58:44 warnings: STATIC: void static_zebra_nht_register(struct static_route *, _Bool): Failure to send nexthop to zebra OK Starting staticd. Looking at the installed routes, it looks ok, except for one which I must be missing something obvious, but its ok on quagga and frr6 I have interface igb1.6: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500         options=600703<RXCSUM,TXCSUM,TSO4,TSO6,LRO,RXCSUM_IPV6,TXCSUM_IPV6>         ether 90:e2:ba:01:37:81         inet6 fe80::92e2:baff:fe01:3781%igb1.6 prefixlen 64 scopeid 0xe         inet 64.7.149.177 netmask 0xfffffffc broadcast 64.7.149.179 and a static route of ip route 10.87.1.0/30 64.7.149.178 It ends up installing this static route on the discard interface for some reason on frr7.  On frr6, it works. next hop is 64.7.149.178. I do get the same warning messages however at  startup. On frr5, its the same as frr7.  # vtysh -c "show ip route 10.87.1.0/30" Routing entry for 10.87.1.0/30   Known via "static", distance 1, metric 0, best   Last update 00:00:14 ago     64.7.149.178 (recursive)   *   10.129.129.1, via disc0 kernel confirms # netstat -nr | grep ^10.87.1. 10.87.1.0/30       10.129.129.1       UG1       disc0 # Any ideas what up ?  As this is just a test box, there is no MAC addr for the next hop, but would it not mark the route as inactive rather than change the next hop to the discard interface ?     ---Mike -- ------------------- Mike Tancsa, tel +1 519 651 3400 x203 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada