Routing

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  • 1.  MX204. Routing problem with directly connected route

    Posted 01-26-2023 03:13

    hi!

    I need your help!

    I have a problem:

    Configured on one of the interfaces the xx.xx.xx.120/30 network,

    which is part of the larger xx.xx.xx.0/18 network. xx.xx.xx.0/18 is announced to BGP upstreams.

    I do not see from the world a network terminated on one of the router interfaces

    Symptoms:

    Ping and trace to hosts in the world from the client network and back does not work.

    Config:

    # show interfaces et-0/0/0
        vlan-tagging;
        unit 564 {
            description test_net;
            vlan-id 564;
            family inet {
                filter {
                    input test_filter;
                    output test_filter;
                }
                address xx.xx.xx.121/30;
        }
    
    ----------------------------------
    
    # show firewall filter test_filter
    term 1 {
        then accept;
    }
    
    ----------------------------------
    
    xx.xx.xx.120/30  *[Direct/0] 1w3d 09:39:31
                        > via et-0/0/0.564
    xx.xx.xx.121/32  *[Local/0] 1w3d 09:39:31
                          Local via et-0/0/0.564
    # show interfaces lo0
    unit 0 {
        family inet {
            filter {
                input filter_to_me;
            }
            address 127.0.0.1/32;
        }
    
    ----------------------------------
    
    # show firewall family inet filter filter_to_me
    term 1 {
        then accept;
    }

    This network advertised to "World":

    # show routing-options static
    route xx.xx.xx.0/18 {
        discard;
        community [ yyyyy:0 yyyyy:100 yyyyy:110 yyyyy:102 yyyyy:60 ];
    }
    
    ----------------------------------
    
    show route advertising-protocol bgp ISP1_peer_ip 
    
    inet.0: 921682 destinations, 3815557 routes (891246 active, 0 holddown, 587001 hidden)
      Prefix                  Nexthop              MED     Lclpref    AS path
    * xx.xx.xx.0/18         Self                                    I
    
    ​There are multiple BGP peerings configured on the router from which I get full view.
    Allowed everything on incoming and outgoing policies, but the problem remained.

    I can't understand why my network xx.xx.xx.120/30 isn't working.


  • 2.  RE: MX204. Routing problem with directly connected route

    Posted 01-26-2023 20:18
    For the ping to work in both directions you need to complete the route checks on both sides. 
    • You are sending the prefix xx.xx.xx.0/18
    • Can you confirm with the ISP1_peer_ip route mirror that your prefix xx.xx.xx.0/18 is accepted and installed.
    • Can you confirm you have a local full table or default route out to ISP1_peer_ip for the return traffic
    Also if you have all full tables and multiple ISP you may also be dealing with some asymmetrical routing that might affect results.

    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
    http://puluka.com/home
    ------------------------------