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BGP Routing to available address

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  • 1.  BGP Routing to available address

     
    Posted 04-04-2018 01:32

    Hi,

     

    Just some nigly results from testing. I have the following setup:

     

    DNS (192.168.1.1/29) --> (192.168.1.2/29) SRX (192.168.100.1/30) --> (192.168.100.2/30) Core1 (172.16.16.1/30) --> (172.16.16.2/30) BGP

     

    So, here is the result of ping test from BGP router:

     

    Ping to 172.16.16.1 - Success

    Ping to 192.168.100.2 - Success

    Ping to 192.168.100.1 - success

    Ping to 192.168.1.2 - Success

    Ping to 192.168.1.1 - Failure

     

    Yet, if I ping all those addresses from the Core1 router, they are all available. Now, at first I thought it could be an address issue or a filter on the core, but it can't be. If the BGP can ping the SRX address and receive a response, it should also be able to ping the DNS interface and receive a response because it is on the same network.

     

    Any help would be greatly appreciated.

     

    Thanks

     



  • 2.  RE: BGP Routing to available address

    Posted 04-04-2018 02:37
    Just a thought. Do you see the reverse route for the source IP on DNS?


  • 3.  RE: BGP Routing to available address

     
    Posted 04-04-2018 08:25

    Hi Kingsman,


    From the SRX address (Facing the DNS) and routing-instance ninegroup-dns, I can ping the BGP router interface.... I cannot test from the DNS server itself as the systems guy is currently off sick.....

     

    The traceroute to both addresses seems fine..... although to the SRX it gets as far as the Logical Tunnel interface and then stops... but that's weird because it uses the same route to get to the physical interface facing the DNS.... 



  • 4.  RE: BGP Routing to available address

    Posted 04-04-2018 08:44
    I have seen such issue where missing route on the server caused this type of issue.

    You can ask your server guy to try ping/traceroute from DNS to BGP router and check. They may need to add a route in the DNS server.


  • 5.  RE: BGP Routing to available address

     
    Posted 04-05-2018 00:45

    Hi Kingsman,

     

    Yes, I can get him to give it a try..... but from an anycast perspective it utilises IS-IS and is being advertised as should be. There is a static route on the SRX to the DNS Server for the Anycast and that is re-distributed into IS-IS.

     

    I will ask him.... I'll let you know the results.

     



  • 6.  RE: BGP Routing to available address
    Best Answer

     
    Posted 04-05-2018 06:46

    Hi Kingsman,

     

    Problem resolved and now working. I cannot tell you the exact details as it involves our public IP addressing, but safe to say the internal network was allowed and external not. So I changed the BGP peering to be in the internal range and it all started working. 

     

    Not being able to see the DNS configuration did not help

     

    Thanks