I'm new to networking and I'm currently learning about IPv6 in static routing. I set up an environment in Cisco Packet Tracer like this: have connected two routers with serial medium , each router with a switch with a copper straight-through medium in GigabitEthernet interface and with FastEthernet interface I have connected each switch with each computer. And these are the commands for the routers:

R1 Configuration

R1(config) # interface GigabitEthernet 0/0
R1(config-if ) # ipv6 address 2001:DB8:ACAD:A::/64 eui-64
R1(config- if ) # no shutdown
R1(config-if ) # exit
R1(config) # interface Serial 0/1/0
R1(config) # ipv6 address FC00::1/64
R1(config- if ) # no shutdown
R1(config-if ) # exit
R1(config) #ipv6 ipv6 unicast-routing
R1(config) # ipv6 route 2001:DB8:ACAD:B::/64 Serial0/1/0
R1(config-if ) # exit

R2 Configuration

R2(config) # interface GigabitEthernet 0/0
R2(config-if ) # ipv6 address 2001:DB8:ACAD:B::/64 eui-64
R2(config- if ) # no shutdown
R2(config-if ) # exit
R2(config) # interface Serial 0/1/0
R2(config) # ipv6 address FC00::2/64
R2(config- if ) # no shutdown
R2(config-if ) # exit
R2(config) #ipv6 ipv6 unicast-routing
R2(config) # ipv6 route 2001:DB8:ACAD:A::/64 Serial0/1/0
R2(config-if ) # exit

Pc1: IPV6 address is : 2001:DB8:ACAD:A::F /64 and default gateway is : 2001:DB8:ACAD:A::1. / 2001:DB8:ACAD:B::1 and IPV6 addres : 2001:DB8:ACAD:B::F for the second pc. When Itry to ping nothing happens though.What have I done wrong?

  • You are also using invalid addressing on your serial interfaces. The fc00::/10 addressing used to be Site-Local addressing, but that was deprecated years ago: "Site-Local addresses were originally designed to be used for addressing inside of a site without the need for a global prefix. Site-local addresses are now deprecated as defined in [SLDEP]...The special behavior of this prefix defined in [RFC3513] must no longer be supported in new implementations."
    – Ron Maupin
    Commented Jun 10, 2020 at 12:08
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer.
    – Ron Maupin
    Commented Dec 17, 2020 at 17:45

2 Answers 2


Set your routes to an address, not an interface. Simply putting the packet on the serial interface will not work. (it's not a bridge)


You say:

Pc1: [...] default gateway is : 2001:DB8:ACAD:A::1.

But your router does not have that address. Check this example:

R1#show running-config | section interface Serial3/0
interface Serial3/0
 no ip address
 ipv6 address 2001:DB8:ACAD:A::/64 eui-64

R1#show ipv6 interface Serial3/0 | section Global
  Global unicast address(es):
    2001:DB8:ACAD:A:C802:DCFF:FE4A:8, subnet is 2001:DB8:ACAD:A::/64 [EUI]

Observe how the router does not have the 2001:DB8:ACAD:A::1 address you expected. Instead, it used SLAAC to define its own IPv6 address. This is because you specified the eui-64 keyword.

So, the gateway address in PC1 does not match the address in the router. You may either change the gateway address in PC1 or manually assign the address in the router.

If you want to manually set the IPv6 address instead of using SLAAC, define it in the same way you did for the Serial port: just ipv6 address 2001:DB8:ACAD:A::1/64.

You should remove the other one using no ipv6 address 2001:DB8:ACAD:A::/64 eui-64 as it will not get automatically removed.

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