Announce ipv6 routes in bgp

RouterOS Forwarding Protocols
1

I would like someone to help me, I really need to do a filter to announce my ipv6 block to the operator, and block the millions of routes received by her.

2

Simply ask the operator to provide you only default route, and nothing more.

3

AND HOW DO I MAKE HIM SEE MY ROUTES, WHY HE CLAIMS I'M NOT ADVERTISEMENT ANY ROUTE

4

Here is an IPv6 filtering example for advertised prefixes from a blog post I wrote:

https://stubarea51.net/2021/08/24/mikrotik-routerosv7-first-look-feedback-on-routing-filters/

/routing filter rule
add chain=dead.beef.101 rule="if (dst==200:dead:beef:101::/64) {accept}"
add chain=dead.beef.102 rule="if (dst==200:dead:beef:102::/64) {accept}"
add chain=dead.beef.agg rule="if (dst in 200:dead:beef::/48) {accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.101) {set bgp-local-pref 300; accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.102) {accept}"
add chain=bgp-out-v6 rule="if (chain dead.beef.agg && dst-len<128) {set bgp-local-pref 150; accept}"
5

Hardware and RouterOS used is not specified.

6

SORRY BUT IN THIS VERSION I’M BAD STILL, COULD MODIFY JA RULE FOR MY BLOCK ALREADY. FOLLOW THE BLOCK BELOW,

2804:284c::/32

HOW WOULD THE RULE BE?

7

You still haven’t specified which RouterOS you are using.

8

I'm currently using RouterOS 7.2.1 and I'm thinking of upgrading to the latest one, 7.3.1

9

make sure you have an active route with type = blackhole for the subnet or prefix you want to announce otherwise it won’t work because no synchronize is no longer available on ROS v7
and also connection->filter section output.network = bgp-networks should match and have entry on your ipv6 address list

/ipv6 firewall address-list
add address=2804:284c::/32  list=bgp-networks

/routing filter rule
add chain=bgp-out-v6 rule="if (dst in 2804:284c::/32 && dst-len >= 32 && protocol bgp) { accept }"

just my 0.2$

10

Create loopback interface (ej. bridge with no actual interfaces attached to it ) then set the advertised prefix /address to that interface. Considering you already got the BGP session established and the output prefix correctly set on bgp out filter. I had the same issue and got it solved this way.

Cheers!

11

Same issue, unfortunately I can’t find much documentation about ipv6 bgp on routeros 7+

12

@itrack, describe your problem and show your configuration.

13

Hi @jardielroque

In order for you to set this up you need 3 things:

  1. Routing Filters

  2. Address List

  3. Existing routes

#1. Routing Filters - IPv6 filters (OUT advertises our IPv6 prefix, IN accepts default route only)

/routing filter rule add chain=bgp-ipt-out disabled=no rule="if (dst == 2804:284c::/32) { accept }”
/routing filter rule add chain=bgp-ipt-in disabled=no rule="if (dst == ::/0) { accept }”

#dst == ::/0 # exactly default only
#dst in ::/0 # literally everything (do not do this unless you need it)

#2. Address List
/ipv6 firewall address-list
add address=2804:284c::/32 list=acl-ipt-out

#3. Existing routes
/ipv6 route add blackhole dst-address=2804:284c::/32

Once this is done you can print to confirm your v6 advertisement after you applied the in/out filters and the output network.

/routing bgp advertisements print where peer="IPv6-peer-name-1" #Check session name

If this still doesn’t solve your advertisement issue you can just post the output of your Filter, IPv6 Address list, IPv6 Routes and BGP peer.

Have a great day :slight_smile: