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Maniphest T1222

OSPF routing problem - route looping
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Description

If on two routers with the redistribution of static routes enabled, create the same routes and then delete them, the route will loop.

сonfiguration router 1 (vyos1):

interfaces {
    ethernet eth0 {
        address 192.168.0.1/24
    }
    loopback lo {
    }
}
protocols {
    ospf {
        area 0 {
            network 192.168.0.0/24
        }
        redistribute {
            static {
            }
        }
    }
}
service {
    ssh {

сonfiguration router 2 (vyos2):

interfaces {
    ethernet eth0 {
        address 192.168.0.2/24
    }
    loopback lo {
    }
}
protocols {
    ospf {
        area 0 {
            network 192.168.0.0/24
        }
        redistribute {
            static {
            }
        }
    }
}
service {
    ssh {
vyos@vyos1:~$ show ip ospf neighbor 

Neighbor ID     Pri State           Dead Time Address         Interface            RXmtL RqstL DBsmL
192.168.0.2       1 Full/DR           31.039s 192.168.0.2     eth0:192.168.0.1         0     0     0

Create a route on a router 1:

vyos@vyos1:~$ conf
vyos@vyos1# set protocols static route 192.168.100.0/24 blackhole 
vyos@vyos1# commit
vyos@vyos1# exit
vyos@vyos2:~$ show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route

O   192.168.0.0/24 [110/1] is directly connected, eth0, 00:08:04
C>* 192.168.0.0/24 is directly connected, eth0, 00:09:19
O>* 192.168.100.0/24 [110/20] via 192.168.0.1, eth0, 00:01:03

Create a route on a router 2:

vyos@vyos2:~$ conf
vyos@vyos2# set protocols static route 192.168.100.0/24 blackhole
vyos@vyos2:~$ show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route

O   192.168.0.0/24 [110/1] is directly connected, eth0, 00:09:59
C>* 192.168.0.0/24 is directly connected, eth0, 00:11:14
S>* 192.168.100.0/24 [1/0] unreachable (blackhole), 00:00:30
O   192.168.100.0/24 [110/20] via 192.168.0.1, eth0, 00:00:40

Remove the route on both routers:

vyos@vyos1# delete protocols static route 192.168.100.0/24
vyos@vyos1# commit
vyos@vyos2# delete protocols static route 192.168.100.0/24
vyos@vyos2# commit

And show:

vyos@vyos1:~$ show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route

O   192.168.0.0/24 [110/1] is directly connected, eth0, 00:11:31
C>* 192.168.0.0/24 is directly connected, eth0, 00:13:28
O>* 192.168.100.0/24 [110/20] via 192.168.0.2, eth0, 00:02:47
vyos@vyos2:~$ show ip route 
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route

O   192.168.0.0/24 [110/1] is directly connected, eth0, 00:11:28
C>* 192.168.0.0/24 is directly connected, eth0, 00:12:43
O>* 192.168.100.0/24 [110/20] via 192.168.0.1, eth0, 00:02:09

Now I got a route loop. The problem is solved by rebooting routers.

Details

Version
1.2
Is it a breaking change?
Perfectly compatible
Issue type
Bug (incorrect behavior)

Event Timeline

daniil created this task.Jan 31 2019, 4:41 PM
daniil updated the task description. (Show Details)Jan 31 2019, 4:53 PM
daniil updated the task description. (Show Details)
daniil updated the task description. (Show Details)Jan 31 2019, 4:56 PM
syncer assigned this task to dmbaturin.Feb 5 2019, 2:21 PM
syncer triaged this task as Normal priority.
syncer edited projects, added: VyOS 1.3 Equuleus; removed: VyOS 1.2 Crux.
pasik subscribed.Feb 5 2019, 7:43 PM
byabcz subscribed.May 1 2019, 5:55 PM
Viacheslav closed this task as Resolved.Jul 27 2020, 2:29 PM
Viacheslav subscribed.

Fixed, VyOS 1.3-rolling-202007270117

vyos@r1-roll# run show ip route

S>* 0.0.0.0/0 [1/0] via 192.168.122.1, eth0, 00:23:35
O   10.0.0.0/30 [110/1] is directly connected, eth1, 00:02:06
C>* 10.0.0.0/30 is directly connected, eth1, 00:03:21
S>* 192.168.100.0/24 [1/0] unreachable (blackhole), 00:00:03
O   192.168.100.0/24 [110/20] via 10.0.0.2, eth1, 00:00:20
C>* 192.168.122.0/24 is directly connected, eth0, 00:23:39

on R2 delete route

delete protocols static route 192.168.100.0/24
commit

On R1 route not present

vyos@r1-roll# run show ip route

S>* 0.0.0.0/0 [1/0] via 192.168.122.1, eth0, 00:24:14
O   10.0.0.0/30 [110/1] is directly connected, eth1, 00:02:45
C>* 10.0.0.0/30 is directly connected, eth1, 00:04:00
C>* 192.168.122.0/24 is directly connected, eth0, 00:24:18
c-po moved this task from Need Triage to Finished on the VyOS 1.3 Equuleus board.Aug 3 2020, 2:15 PM
dmbaturin edited projects, added: VyOS 1.3 Equuleus (1.3.0-epa1); removed: VyOS 1.3 Equuleus.Sep 11 2021, 1:52 AM
dmbaturin set Is it a breaking change? to Perfectly compatible.Sep 29 2021, 1:35 PM
dmbaturin set Issue type to Bug (incorrect behavior).