ecc8366215fac8a1f5649f7464e713bbf4c0a47b
howto/mikrotik/How-to-setup-slash-32-address-on-GRE-or-Point-to-Point-link-on-Mikrotik-RouterOS.md
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1 | -## RouterOS issues |
|
2 | - |
|
3 | - * RouterOS doesn't have direct Point-to-Point addresses. |
|
4 | - * BGP doesn't resolve the next-hop for their routes using a rescursive route that uses a interface as next-hop |
|
5 | - |
|
6 | -The long explanation about how mikrotik resolves recursive routes is documentated at [Mikrotik's page](https://wiki.mikrotik.com/wiki/Manual:IP/Route#Nexthop_lookup). |
|
7 | - |
|
8 | -How can we workaround these issues? Simple. We setup a /32 on the Point-to-Point interface, we setup a direct route to our to other peer (using the interface as next-hop for this route) and use bgp filters to change the next-hop interface. |
|
9 | - |
|
10 | -## Legend |
|
11 | - |
|
12 | - * 172.24.0.1 -> Your /32 inside tunnel address |
|
13 | - * 172.26.2.2 -> Peer's /32 inside tunnel address. |
|
14 | - * gre-dn42-peer -> This is the name of the interface |
|
15 | - * 1.1.1.1 - peer external IP |
|
16 | - * 2.2.2.2 - your external IP |
|
17 | - * bgp-dn42-peer-in -> This is the name of the chain filter. You should use a different chain per point to point link |
|
18 | - |
|
19 | -## Setup |
|
20 | - |
|
21 | -You create the GRE interface in the same way the [Mikrotik Guide](/howto/mikrotik) does. |
|
22 | - |
|
23 | -``` |
|
24 | -/interface gre |
|
25 | -add allow-fast-path=no comment="DN42 somepeer" local-address=2.2.2.2 name=gre-dn42-peer \ |
|
26 | -remote-address=1.1.1.1 |
|
27 | -``` |
|
28 | - |
|
29 | -Next you add the /32 address on the interface. You can install this address on a loop interface (on RouterOS this means an empty bridge) if you plan to use the same address over several GRE tunnels or other OpenVPN interfaces. |
|
30 | - |
|
31 | -``` |
|
32 | -/ip address add address=172.24.0.1/32 interface=gre-dn42-peer |
|
33 | -``` |
|
34 | - |
|
35 | -Next, we add the direct route as next-hop using the interface |
|
36 | - |
|
37 | -``` |
|
38 | -/ip route add distance=1 dst-address=172.26.2.2/32 gateway=gre-dn42-peer pref-src=172.24.0.1 |
|
39 | -``` |
|
40 | - |
|
41 | -At this point, the ping with the peer should work. Also, the bgp session can be established, but the routes will not work. We need a input filter to fix the next-hop routes. |
|
42 | - |
|
43 | -``` |
|
44 | -/routing filter add chain=bgp-dn42-peer-in protocol=bgp set-in-nexthop-direct=gre-dn42-peer |
|
45 | -``` |
|
46 | - |
|
47 | -if you have other global input chain filters, you should add a jump in the same chain, like this: |
|
48 | -``` |
|
49 | -/routing filter add action=jump chain=bgp-dn42-peer-in protocol=bgp jump-target=bgp-global-dn42-input |
|
50 | -``` |
|
51 | - |
|
52 | -If you haven't created the BGP session, create it now from the [Mikrotik guide](/howto/mikrotik#how-to-connect-to-dn42-using-mikrotik-routeros_bgp). Change the peer input filter to use the chain we've just created: |
|
53 | - |
|
54 | -``` |
|
55 | -/routing bgp peer set bgp-dn42-somename in-filter=bgp-dn42-peer-in |
|
56 | -``` |
|
57 | - |
|
58 | -With this fix, all the routes will have set next-hop the GRE interface and there will be no need to use RouterOS' recursive route resolve. |
|
59 | - |
|
60 | -Check the routes with: |
|
61 | -``` |
|
62 | -/ip routes print detail where received-from=bgp-dn42-somename |
|
63 | -``` |
|
64 | - |
|
65 | -There should an attribute like: |
|
66 | -``` |
|
67 | -gateway=gre-dn42-peer gateway-status=gre-dn42-peer reachable |
|
68 | -``` |
|
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howto/mikrotik/ptp32.md
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1 | +## RouterOS issues |
|
2 | + |
|
3 | + * RouterOS doesn't have direct Point-to-Point addresses. |
|
4 | + * BGP doesn't resolve the next-hop for their routes using a rescursive route that uses a interface as next-hop |
|
5 | + |
|
6 | +The long explanation about how mikrotik resolves recursive routes is documentated at [Mikrotik's page](https://wiki.mikrotik.com/wiki/Manual:IP/Route#Nexthop_lookup). |
|
7 | + |
|
8 | +How can we workaround these issues? Simple. We setup a /32 on the Point-to-Point interface, we setup a direct route to our to other peer (using the interface as next-hop for this route) and use bgp filters to change the next-hop interface. |
|
9 | + |
|
10 | +## Legend |
|
11 | + |
|
12 | + * 172.24.0.1 -> Your /32 inside tunnel address |
|
13 | + * 172.26.2.2 -> Peer's /32 inside tunnel address. |
|
14 | + * gre-dn42-peer -> This is the name of the interface |
|
15 | + * 1.1.1.1 - peer external IP |
|
16 | + * 2.2.2.2 - your external IP |
|
17 | + * bgp-dn42-peer-in -> This is the name of the chain filter. You should use a different chain per point to point link |
|
18 | + |
|
19 | +## Setup |
|
20 | + |
|
21 | +You create the GRE interface in the same way the [Mikrotik Guide](/howto/mikrotik) does. |
|
22 | + |
|
23 | +``` |
|
24 | +/interface gre |
|
25 | +add allow-fast-path=no comment="DN42 somepeer" local-address=2.2.2.2 name=gre-dn42-peer \ |
|
26 | +remote-address=1.1.1.1 |
|
27 | +``` |
|
28 | + |
|
29 | +Next you add the /32 address on the interface. You can install this address on a loop interface (on RouterOS this means an empty bridge) if you plan to use the same address over several GRE tunnels or other OpenVPN interfaces. |
|
30 | + |
|
31 | +``` |
|
32 | +/ip address add address=172.24.0.1/32 interface=gre-dn42-peer |
|
33 | +``` |
|
34 | + |
|
35 | +Next, we add the direct route as next-hop using the interface |
|
36 | + |
|
37 | +``` |
|
38 | +/ip route add distance=1 dst-address=172.26.2.2/32 gateway=gre-dn42-peer pref-src=172.24.0.1 |
|
39 | +``` |
|
40 | + |
|
41 | +At this point, the ping with the peer should work. Also, the bgp session can be established, but the routes will not work. We need a input filter to fix the next-hop routes. |
|
42 | + |
|
43 | +``` |
|
44 | +/routing filter add chain=bgp-dn42-peer-in protocol=bgp set-in-nexthop-direct=gre-dn42-peer |
|
45 | +``` |
|
46 | + |
|
47 | +if you have other global input chain filters, you should add a jump in the same chain, like this: |
|
48 | +``` |
|
49 | +/routing filter add action=jump chain=bgp-dn42-peer-in protocol=bgp jump-target=bgp-global-dn42-input |
|
50 | +``` |
|
51 | + |
|
52 | +If you haven't created the BGP session, create it now from the [Mikrotik guide](/howto/mikrotik#how-to-connect-to-dn42-using-mikrotik-routeros_bgp). Change the peer input filter to use the chain we've just created: |
|
53 | + |
|
54 | +``` |
|
55 | +/routing bgp peer set bgp-dn42-somename in-filter=bgp-dn42-peer-in |
|
56 | +``` |
|
57 | + |
|
58 | +With this fix, all the routes will have set next-hop the GRE interface and there will be no need to use RouterOS' recursive route resolve. |
|
59 | + |
|
60 | +Check the routes with: |
|
61 | +``` |
|
62 | +/ip routes print detail where received-from=bgp-dn42-somename |
|
63 | +``` |
|
64 | + |
|
65 | +There should an attribute like: |
|
66 | +``` |
|
67 | +gateway=gre-dn42-peer gateway-status=gre-dn42-peer reachable |
|
68 | +``` |
|
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