Recursive routing to a dynamic default route error

RouterOS General
1

After updating to ROS 6.40.7 (latest bugfix release), routes that recursively resolve to the default route are always unreachable.

/ip route
add distance=1 dst-address=18.232.39.253/32 gateway=1.1.1.1 target-scope=30 comment="unreachable after update to 6.40.7"
add distance=1 dst-address=18.232.39.255/32 gateway=isp-1 target-scope=30 comment="Works with interface name"

A PPPoE connection adds the dynamic default route:

dst-address=0.0.0.0/0 gateway=isp-1 reachable distance=1 scope=30 target-scope=10

I don’t remember the version of ROS I was running before the update.
If I specify the interface name as the gateway, it works.

How can I debug this?

2

I have reproduced the problem in a clean installation of ROS 6.40.7 in VirtualBox.

With a static default route, the route to 100.100.100.100/32 is correctly recursively resolved to 172.20.0.1.


> ip address print detail  
Flags: X - disabled, I - invalid, D - dynamic 
 0   address=172.20.33.1/16 network=172.20.0.0 interface=real-world 
     actual-interface=real-world 

> ip route print detail    
Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 0 A S  dst-address=0.0.0.0/0 gateway=172.20.0.1 
        gateway-status=172.20.0.1 reachable via  real-world distance=1 scope=30 
        target-scope=10 

 1 A S  dst-address=100.100.100.100/32 gateway=1.1.1.1 
        gateway-status=1.1.1.1 recursive via 172.20.0.1 real-world distance=1 
        scope=30 target-scope=30 

 2 ADC  dst-address=172.20.0.0/16 pref-src=172.20.33.1 gateway=real-world 
        gateway-status=real-world reachable distance=0 scope=10

But when the default route is dynamic - installed by a client PPPoE connection - the same route to 100.100.100.100/32 is unreachable.


> ip address print detail  
Flags: X - disabled, I - invalid, D - dynamic 
 0   address=172.20.33.1/16 network=172.20.0.0 interface=real-world 
     actual-interface=real-world 

 1 D address=5.0.0.5/32 network=5.0.0.0 interface=isp-1 actual-interface=isp-1 

> ip route print detail 
Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 0 ADS  dst-address=0.0.0.0/0 gateway=isp-1 gateway-status=isp-1 reachable 
        distance=1 scope=30 target-scope=10 

 1 ADC  dst-address=5.0.0.0/32 pref-src=5.0.0.5 gateway=isp-1 
        gateway-status=isp-1 reachable distance=0 scope=10 

 2   S  dst-address=100.100.100.100/32 gateway=1.1.1.1 
        gateway-status=1.1.1.1 unreachable distance=1 scope=30 target-scope=30 

 3 ADC  dst-address=172.20.0.0/16 pref-src=172.20.33.1 gateway=real-world 
        gateway-status=real-world reachable distance=0 scope=10
3

I downgraded to version 6.30.1 in VirtualBox, and it works as expected in this version: 100.100.100.100/32 is reachable through the remote address of the PPPoE connection.


> ip address print detail 
Flags: X - disabled, I - invalid, D - dynamic 
 0   address=172.20.33.1/16 network=172.20.0.0 interface=real-world 
     actual-interface=real-world 

 1 D address=5.0.0.5/32 network=5.0.0.0 interface=isp-1 actual-interface=isp-1

> ip route print detail   
Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 0 ADS  dst-address=0.0.0.0/0 gateway=5.0.0.0 
        gateway-status=5.0.0.0 reachable via  isp-1 distance=0 scope=30 
        target-scope=10 

 1 ADC  dst-address=5.0.0.0/32 pref-src=5.0.0.5 gateway=isp-1 
        gateway-status=isp-1 reachable distance=0 scope=10 

 2 A S  dst-address=100.100.100.100/32 gateway=1.1.1.1 
        gateway-status=1.1.1.1 recursive via 5.0.0.0 isp-1 distance=1 scope=30 
        target-scope=30 

 3 ADC  dst-address=172.20.0.0/16 pref-src=172.20.33.1 gateway=real-world 
        gateway-status=real-world reachable distance=0 scope=10
4

Don’t think you can do next hop / recursive via interface routing, must be IP Address, see difference here between not working and working:
Capture.JPG

5

The routes you highlighted are added by ROS itself, when the PPPoE client connection is established. The configuration of the client and the PPPoE server have not been changed.

Can I make ROS use the IP address again?

6

What you can do is:

to disable “add default route” in PPPOE client settings, then create a static route pointing to the IP of the gateway. (Make a comment in this route to check gateway IP if it fails in future, just in case ISP has made IP changes)
Then do Next Hop / Recursive routing via this

7

From the changelog for release 6.40:

*) ppp - use interface name instead of IP as default route gateway;

So this is not a bug, but a feature that has been removed.

Unfortunately, the local and the remote addresses change, so I cannot simply route to the remote address.
I’ll try to work around this problem by setting the remote address in the PPP profile used for my ISP.