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  • 1.  Ipv6 interface connectivity issue

    Posted 10-10-2020 14:18

    Hi all,


    I am currently doing the junos genius JNCIA certification track and have come across an issue i cannot solve. In the Routing Fundamentals lab step 2.1 it instructs to configure the ipv6 address:


    set ge-0/0/1 unit 0 family inet6 address fda1::1/126

    set lo0/0 unit 0 family inet6 address fda9::1/128


    on vSrx1 and fda1::2/126 on vSrx2

    On the next step it issues a successful ping on the local interface


    e.g.  ping fda1::1 rapid count 25 on vSrx1


    I have setup the ipv6 addresses as shown in the lab. However when i issue a ping it just responds with No route to host.

    The ping to the lo0/0 address works fine


    I have issued a run show route command and have noticed that the lo0/0 address is in the routing table but instead of the ipv6 addresses configured on the interface with the /126 mask i have a link local address route in the table instead with a /128 address.


    I believe this to be the issue.


    Is there anyway i can override the link local address with the /126 address?


    I hope i explained that well.


    Thanks for any help



  • 2.  Betreff: Ipv6 interface connectivity issue

    Posted 10-11-2020 11:53

    Hello Eugene,


    please paste the outputs of the following commands of vSRX1:


    show interfaces ge-0/0/1

    show configuration interfaces ge-0/0/1

    show route fda1::1

  • 3.  Betreff: Ipv6 interface connectivity issue

    Posted 10-11-2020 13:34

    Hi F1ght3r,


    Thanks for the reply.


    I forgot to mention im using gns3 and the interface name is em0.


    eugene@vSrx1> show interfaces em0
    Physical interface: em0, Enabled, Physical link is Up
    Interface index: 8, SNMP ifIndex: 17
    Type: Ethernet, Link-level type: Ethernet, MTU: 1514, Speed: 1000mbps
    Device flags : Present Running
    Interface flags: SNMP-Traps
    Link type : Full-Duplex
    Current address: 08:00:27:8d:2e:61, Hardware address: 08:00:27:8d:2e:61
    Last flapped : 2020-10-11 21:37:32 IST (00:53:31 ago)
    Input packets : 0
    Output packets: 7

    Logical interface em0.0 (Index 67) (SNMP ifIndex 18)
    Flags: SNMP-Traps Encapsulation: ENET2
    Input packets : 0
    Output packets: 7
    Protocol inet, MTU: 1500
    Flags: Sendbcast-pkt-to-re, Is-Primary
    Addresses, Flags: Is-Preferred Is-Primary
    Destination:, Local:, Broadcast:
    Protocol inet6, MTU: 1500
    Flags: Is-Primary
    Addresses, Flags: Is-Preferred
    Destination: fe80::/64, Local: fe80::a00:27ff:fe8d:2e61


    eugene@vSrx1> show configuration interfaces em0
    unit 0 {
    family inet {
    family inet6 {
    address fda1::1/126;


    eugene@vSrx1> show route fda1::1


    This has no output



  • 4.  Betreff: Ipv6 interface connectivity issue
    Best Answer

    Posted 10-11-2020 14:11

    Hello Eugene,


    personally I have no experience with vSRX and GNS3, but from the documentation "em0" on vSRX is just for the cluster control link, "Both em0 and em1 are internal interfaces that connect between the Routing Engine (RE) and the Control Board (CB)."



    What is the reason that you configured the IP address to the em0 interface, and not to any ge-0/0/X interface? You should use the ge-0/0/X interfaces for IP connectivity.

  • 5.  Betreff: Ipv6 interface connectivity issue

    Posted 10-12-2020 03:51

    Hi F1ght3r,


    On gns3 i import the junosOs via virtualbox and all the VM has as interfaces are Ethernet ports so as i add more ports more em0-<num of ports> become available to me on the device. There are no ge interfaces available to me. That's the reason i configured the em interfaces.


    Anyway i tested it on a juniper v-lab and configured the the ge-0/0/0 on a vMx device and the routes worked as expected from the junos labs. I can see the fda1::1/126 route in the routing table and more importantly ping fda1::2/126 on the adjacent router!!


    Thanks for all your help