problem route fitering a subnet

RouterOS Forwarding Protocols
1

Hi all.
I have some routes coming from bgp like:
10.83.1.0/24
…
10.83.200.0/24

If I apply to ebgp connection this filter:
/chain=drop10 prefix=10.83.1.0/24 action=discard

it correctly remove the corresponding route.

If I apply this filter
/chain=drop10 prefix=10.0.0.0/8 action=discard
or
/chain=drop10 prefix=10.0.0.0 prefix-len=0..8 action=discard
or
/chain=drop10 prefix=10.0.0.0 prefix-len=9..32 action=discard

it drop nothing.

How it is possibile to write a rule which drops a set of routes?

Thanks

2

If you expand the filters you have above, none of them will match the routes you’ve listed above.

Can you try the following and see if it matches, please?

/chain=drop10 prefix=10.0.0.0/8 prefix-len=24 action=discard

http://wiki.mikrotik.com/wiki/Manual:Routing/Routing_filters

If network mask is not set, /32 is assumed

Regards,

3

thanks cupis,
/chain=drop10 prefix=10.0.0.0/8 prefix-len=24 action=discard

works correctly.

now it remains some subnets to filter:

  • 10.245.1.0/29
  • 10 250.1.0/30
    …

is it possible to filter all subnets 10.x.x.x/x ?

4

Yes, use something like:

/chain=drop10 prefix=10.0.0.0/8 prefix-len=8-32 action=discard

This will filter all routes in 10.0.0.0/8, with any prefix from /8 down to /32.

Regards,

5

it works!
thanks