Hello,
Im using /24 prefix for BGP.
When I was using Routeros 6 I disable synchronize and I can use /25-/26 etc. prefix on my router.
In Ros7 this is no synchronize button. How can I do this ?
Thanks.
Re: Routeros 7 BGP Using Smaller Prefix [SOLVED]
Hi,
Make a route with a type of blackhole
https://help.mikrotik.com/docs/display/ ... g+Examples
/ip/firewall/address-list/
add list=bgp-networks address=192.168.0.0/24
/ip/route
add dst-address=192.168.0.0/24 blackhole
/routing/bgp/connection
set peer_name output.network=bgp-networks
and also check your upstream because the smallest prefix you can advertise is /24
Make a route with a type of blackhole
https://help.mikrotik.com/docs/display/ ... g+Examples
/ip/firewall/address-list/
add list=bgp-networks address=192.168.0.0/24
/ip/route
add dst-address=192.168.0.0/24 blackhole
/routing/bgp/connection
set peer_name output.network=bgp-networks
and also check your upstream because the smallest prefix you can advertise is /24
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gameboys61
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Re: Routeros 7 BGP Using Smaller Prefix
Thanks for reply.
I have real IP like (example: 1.1.1.0/24) .
I advertesing 1.1.1.0/24 .
I want to use 1.1.1.0/25 and 1.1.1.129/25 on my VLAN's.
On routeros6 I can do it with synchronize=no . In routers 7 this is no option.
Do I need to route blackhole ? Its correct ?
I have real IP like (example: 1.1.1.0/24) .
I advertesing 1.1.1.0/24 .
I want to use 1.1.1.0/25 and 1.1.1.129/25 on my VLAN's.
On routeros6 I can do it with synchronize=no . In routers 7 this is no option.
Do I need to route blackhole ? Its correct ?
Re: Routeros 7 BGP Using Smaller Prefix
hi,
yes, just like what i give you in the previous post
yes, just like what i give you in the previous post
Re: Routeros 7 BGP Using Smaller Prefix
Why do you need to advertise something smaller to your BGP neighbors?I have real IP like (example: 1.1.1.0/24) .
I advertesing 1.1.1.0/24 .
I want to use 1.1.1.0/25 and 1.1.1.129/25 on my VLAN's.
Also if you are actually using those two /25s in your network, shouldn't they already be in the table and synchronization shouldn't be an issue?
It's usually good to have a static tie-down route anyway to make sure that your BGP speakers don't revoke prefixes externally because of an IGP issue internally. If you go that route I would make sure to give them a high administrative distance like 254 so that they don't accidentally become the installed route for that prefix over, say, OSPF.
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gameboys61
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Re: Routeros 7 BGP Using Smaller Prefix
Hello,Why do you need to advertise something smaller to your BGP neighbors?I have real IP like (example: 1.1.1.0/24) .
I advertesing 1.1.1.0/24 .
I want to use 1.1.1.0/25 and 1.1.1.129/25 on my VLAN's.
Also if you are actually using those two /25s in your network, shouldn't they already be in the table and synchronization shouldn't be an issue?
It's usually good to have a static tie-down route anyway to make sure that your BGP speakers don't revoke prefixes externally because of an IGP issue internally. If you go that route I would make sure to give them a high administrative distance like 254 so that they don't accidentally become the installed route for that prefix over, say, OSPF.
I want to use 2 x /25 on my router.
Im advertesing /24 to neighbor.
Re: Routeros 7 BGP Using Smaller Prefix
Yeah you shouldn't need to do anything special with BGP then. The /24 covers both /25s so once traffic reaches you your router will just use the more specifics.I want to use 2 x /25 on my router.
Im advertesing /24 to neighbor.
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gameboys61
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Re: Routeros 7 BGP Using Smaller Prefix
Im using router os v7.Yeah you shouldn't need to do anything special with BGP then. The /24 covers both /25s so once traffic reaches you your router will just use the more specifics.I want to use 2 x /25 on my router.
Im advertesing /24 to neighbor.
But its not working.
I added to firewall bgp_out list with a 1.1.1.0/24 .
I adden in my address list I added /25 its not working ( gateway no respond to ping ).
When I was add to /24 on my address list gateway is pingable.
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gameboys61
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Re: Routeros 7 BGP Using Smaller Prefix
Its worked.Hi,
Make a route with a type of blackhole
https://help.mikrotik.com/docs/display/ ... g+Examples
/ip/firewall/address-list/
add list=bgp-networks address=192.168.0.0/24
/ip/route
add dst-address=192.168.0.0/24 blackhole
/routing/bgp/connection
set peer_name output.network=bgp-networks
and also check your upstream because the smallest prefix you can advertise is /24
Thanks.
Re: Routeros 7 BGP Using Smaller Prefix
how do you do this when you have a connection with ipv4 and ipv6 address families ? the connection only have 1 output.network
Do you just make the same address list in both ipv6 address list and ipv4 address lists ?
Do you just make the same address list in both ipv6 address list and ipv4 address lists ?
Re: Routeros 7 BGP Using Smaller Prefix
seb, i think it would be recommendation to have one IPv4 BGP connection and a second, additional, IPv6 BGP connection to the peer.
This way you can define the correct address-list per connection and use separated route filters per ipv4 and ipv6.
And as a bonus you are probably mitigating some surprisingly routing behaviors when advertising ipv4 and ipv6 using the same bgp connection.
This way you can define the correct address-list per connection and use separated route filters per ipv4 and ipv6.
And as a bonus you are probably mitigating some surprisingly routing behaviors when advertising ipv4 and ipv6 using the same bgp connection.
Re: Routeros 7 BGP Using Smaller Prefix
BGP looks for both ipv4 and ipv6 address lists with the same name.