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  1. Ok first question. In you post you have the following below. YOu will notice its pointing to :2:2 however there is no :2:2 network on any of the routers is this a typo did you mean to say :23:23::??? also its a 64 instead of a 128 which is what the loopback is. However maybe all addresses are held within the 128?? So your just pointing to a non-existent address knowing that since the one is a prefix of 128 that can hold all addresses so its being sent that way. very cryptic though and I wanted to confirm.

    if this is just a typo then you might want to fix that one and the one below it to as both refer to a :2:2 where none exist.

    Capture

    also my follow up question is this. a floating route just means you have two static routes and if one goes down there is another one so that is called a floating static route?

  2. Hello Brian

    It seems that @ReneMolenaar is using the 2001:2:2::/64 prefix for the L0 interface on R2 in the first diagram, but when he adds R3 to the topology, he changes it to 2001:23:23::/64. I’ll let him know to change it so that it is consistent all the way through the lesson, either 2:2 or 23:23, including the routing tables.

    Yes. A floating static route is essentially a backup route that is statically configured to have a higher administrative distance than the primary route. This primary route can be a static route as well, or a dynamically configured route. It is the backup static route that is referred to as the floating static route. Note that this is a concept that is used in both IPv4 and IPv6 networks.

    I hope this has been helpful!

    Laz

  3. Hello @lagapides

    Could you please explain why this happens? I just tried to lab it out (using F0/0) and it didn’t work as well

    “Just like with IPv4, it is possible to use an interface as the next hop. This will only work with point-to-point interfaces, If you try this with a FastEthernet interface, you’ll see that the router will accept the command but the ping won’t work. You can’t use this for multi-access interfaces.”

  4. Hello Sales

    It is generally not a good idea to configure default route using only physical interface as next-hop if this physical interface is NOT point-to-point. For example its NOT good to use physical interface as nex-hop if it is an Ethernet interface, because ethernet is broadcast multi access by its nature.

    I suggest you to do small lab about it, it will let you grasp the concept.
    Lets say you have small topology, two inter-connected routers with a few loopbacks configured on them, to simulate networks. Configure loopbacks and link connecting R1 and R2.

    topology

    Just in case you was playing around with pings do the following on both routers.
    Disable ip cef
    R1 & R2 (config)# no ip cef

    Disable route-cache
    R1 & R2 (config)# interface g0/0
    R1 & R2 (config-if)# no ip route-cache
    (now all packets are process-switched)

    Disable proxy ARP
    R1 & R2 (config)# ip arp proxy disable

    Make sure that there are not any additional ARP entries, it should look like this

    R1# show ip arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  12.12.12.1              -   0ccb.bdce.9e00  ARPA   GigabitEthernet0/0
    
    R2# show ip arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  12.12.12.2              -   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    

    If you have additional entries in ARP cache, then delete this entries by
    R1 or R2# clear ip arp <ip_entry>

    Now, on R1 create default route using ethernet interface as next-hop.

    R1(config)# ip route 0.0.0.0 0.0.0.0 gigabitEthernet 0/0
    %Default route without gateway, if not a point-to-point interface, may impact performance
    

    New IOS system should give you this warning.

    As next, go on R2 and create default route using ip address as next-hop.

    R2(config)# ip route 0.0.0.0 0.0.0.0 12.12.12.1

    IOS system should be satisfied, not generating any warning message.

    Do some pings from R2 towards R1 loopbacks.

    R2# ping 1.1.0.1
    R2# ping 1.1.1.1
    R2# ping 1.1.2.1
    R2# ping 1.1.3.1
    

    All pings should be successfull. (To be honest, these pings are successfull only because R2 will use its g0/0 ip address as source of these pings, ip of outgoing interface and that ip is in range of dirrectly connected network for R1. If you will ping with ip source address of any of R2 loopbacks, these pings will fail. Example “ping 1.1.0.1 source 2.2.0.1” will fail.)

    Check out ARP table of R2.

    R2# show arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  12.12.12.1              1   0ccb.bdce.9e00  ARPA   GigabitEthernet0/0
    Internet  12.12.12.2              -   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    

    Do some pings from R1 to R2 loopbacks.

    R1# ping 2.2.0.1
    R1# ping 2.2.1.1
    R1# ping 2.2.2.1
    R1# ping 2.2.3.1
    

    All pings should fail.

    Check out ARP table of R1.

    R1# show arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  2.2.0.1                 0   Incomplete      ARPA   
    Internet  2.2.1.1                 0   Incomplete      ARPA   
    Internet  2.2.2.1                 0   Incomplete      ARPA   
    Internet  2.2.3.1                 0   Incomplete      ARPA   
    Internet  12.12.12.1              -   0ccb.bdce.9e00  ARPA   GigabitEthernet0/0
    Internet  12.12.12.2              7   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    

    As you see, Hardware Addr (MAC) of next-hop is Incomplete, because ethernet is multi-access it was not able to recognize MAC of next-hop. Interface was not identified, Interface row is empty.

    Lets go further and help R1 with his default route issue. Go on R2 and enable Proxy ARP there.
    R2(config)# no ip arp proxy disable

    Now try pings from R1 towards R2 loopbacks.

    R1# ping 2.2.0.1
    R1# ping 2.2.1.1
    R1# ping 2.2.2.1
    R1# ping 2.2.3.1
    

    All pings are working now, everything looks Gucci.

    Check R2 ARP table. Remember that we used default “ip route 0.0.0.0 0.0.0.0 12.12.12.1”, next hop specified with IP.

    R2# show arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  12.12.12.1              6   0ccb.bdce.9e00  ARPA   GigabitEthernet0/0
    Internet  12.12.12.2              -   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    

    That looks good.

    Check R1 ARP table. We used default route “ip route 0.0.0.0 0.0.0.0 g0/0”, next hop specified with outgoing interface.

    R1# show arp
    Protocol  Address          Age (min)  Hardware Addr   Type   Interface
    Internet  2.2.0.1                 0   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    Internet  2.2.1.1                 0   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    Internet  2.2.2.1                 0   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    Internet  2.2.3.1                 0   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    Internet  12.12.12.1              -   0ccb.bdce.9e00  ARPA   GigabitEthernet0/0
    Internet  12.12.12.2             11   0ccb.bd3c.9200  ARPA   GigabitEthernet0/0
    

    Pay attention to Hardware Addr (next hop MAC). There are total 5 entries that have same next hop MAC, that is kinda waste of resources. Do you see that danger lurking behind our back? :sunglasses:

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