Routing Issue (BGP and non BGP)

RouterOS Forwarding Protocols
1

I have 3 sites

Site A - BGP Peer to Internet and Metro Ethernet to Site B

Site B - BGP Peer to Internet and Metro Ethernet to Site A and Site C

Site C - BGP Peer to Internet and Metro Ethernet to Site B

I have 2 - IPV4 /24s that are routed over BGP through the peer at each site.
I have IBGP running between the sites. Each site has a RouterOS box.

Site A also has a /28 that is routed
Site B also has a /29 that is routed
Site C also has a /29 that is routed

The IP addresses from the /24’s work great. The problem is that the smaller subnets are getting redirected to the shorted AS Path and when Site B /29 goes out Site A the routing fails. How do I force traffic from Site A’s /28 to only go out through Site A and the same for Site B and Site C?

I realize that anything utilizing the /28 and /29s will not have the redundancy offered by BGP.

The other option I would like to look into is failing over to a VPN between sites if the Metro Ethernet ever goes down.

Also, is there any way to auto apply firewall rules applying to the /24’s to all of the routers automatically?

Thanks

Scott Hellewell

2

It sounds like you need to look into “source” or “policy” routing, so that any traffic from the /29 is routed to a specific peer, rather than using your main routing table (which may cause the traffic to be sent out via the “incorrect” peer).

Some online examples/documentation:

http://wiki.mikrotik.com/wiki/Manual:PCC
http://farolan.blogspot.com/2009/03/how-to-multi-wan-on-mikrotik-routeros.html

Regards,

3

Thank you for the response. I will take a look at what you have provided and see if I have any more questions.

4

Hi all, I have a problem with creating an instance of BGP. I’m ConnectRetry Timer Expired.
The issue is that my AS in the BGP configuration is 6 digits and when you finish configuring the AS tells me what exchanges as AS = 4.43, instead of telling me AS = 26XXXX.
I need your help please. The version 2.13 is the winbox RouterOS 5.13

5

Hi,

You should probably start a new topic for this issue, perhaps with the subject “32-bit ASN issue”.

Regards,

6

Hi Scott Hellewell

I would like to ask how many connection have to Internet ..?

How man eBGP peer you with other ISP?

To improve the Internal routing.. you should use an IGP protocol like OSPF..

and Advertise the Small network via OSPF.. this protocol will take care of your internal connectivity between your small network as well..


i.g. /routing ospf network add area=backbone network=x.y.z0/28 or /29

Also its will be help full if can draw your network diagram and send it here, will have better look on internal and external network connectivity layout with IP level..

Also I would suggest you to look at my presentation at Dubai MUM its will be help full for you to fix your issue..

http://mum.mikrotik.com/presentations/AE12/ali.pdf

good Luck

with my best regards
Ali.