IPv6: Configuring Automatic 6to4
tunnels
·
Automatic
6to4 tunnels are multipoint by default.
·
This
is used for IPv6/IPv4
·
Only
source is mentioned
·
Since
the tunnel is automatic tunnel, we need not mention the tunnel destination.
·
Tunnel
mode is set to ipv6ip 6to4
·
Tunnel
interface is assigned with ipv6 address, which uses special addressing, 2002
followed by the translated IPv4 address of the interface on the router.
·
Let
me take a small 3 roter topology for creating 6to4 tunnels:
Let
me see the configs before creating tunnels:
R1(config-router)#do
show run int fa0/0
Building configuration...
Current configuration : 94 bytes
!
interface FastEthernet0/0
ip address
10.1.12.1 255.255.255.0
duplex auto
speed auto
end
R1(config-router)#do
show run int loop0
Building configuration...
Current configuration : 63 bytes
!
interface Loopback0
ip address
1.1.1.1 255.255.255.255
end
R1(config-router)#do
show ip route ospf
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2
[110/11] via 10.1.12.2, 00:14:32, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O
3.3.3.3 [110/21] via 10.1.12.2, 00:14:32, FastEthernet0/0
10.0.0.0/24 is subnetted, 2 subnets
O
10.1.23.0 [110/20] via 10.1.12.2, 00:14:32, FastEthernet0/0
R1(config-router)#do
ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/28/72 ms
R1(config-router)#do
ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/24/56 ms
R1(config-router)#
R2(config-router)#do
show run int fa0/0
Building configuration...
Current configuration : 94 bytes
!
interface FastEthernet0/0
ip address
10.1.12.2 255.255.255.0
duplex auto
speed auto
end
R2(config-router)#do
show run int fa0/1
Building configuration...
Current configuration : 94 bytes
!
interface FastEthernet0/1
ip address
10.1.23.2 255.255.255.0
duplex auto
speed auto
end
R2(config-router)#do
show run int loop0
Building configuration...
Current configuration : 63 bytes
!
interface Loopback0
ip address
2.2.2.2 255.255.255.255
end
R2(config-router)#do
show ip route ospf
1.0.0.0/32 is subnetted, 1 subnets
O
1.1.1.1 [110/11] via 10.1.12.1, 00:15:17, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O
3.3.3.3 [110/11] via 10.1.23.3, 00:15:17, FastEthernet0/1
R2(config-router)#do
ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/20/44 ms
R2(config-router)#do
ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/25/68 ms
R2(config-router)#
R3(config-router)#do
show run int fa0/1
Building configuration...
Current configuration : 94 bytes
!
interface FastEthernet0/1
ip address
10.1.23.3 255.255.255.0
duplex auto
speed auto
end
R3(config-router)#do
show run int loop0
Building configuration...
Current configuration : 63 bytes
!
interface Loopback0
ip address
3.3.3.3 255.255.255.255
end
R3(config-router)#do
show ip route ospf
1.0.0.0/32 is subnetted, 1 subnets
O
1.1.1.1 [110/21] via 10.1.23.2, 00:22:13, FastEthernet0/1
2.0.0.0/32 is subnetted, 1 subnets
O
2.2.2.2 [110/11] via 10.1.23.2, 00:22:13, FastEthernet0/1
10.0.0.0/24 is subnetted, 2 subnets
O
10.1.12.0 [110/20] via 10.1.23.2, 00:22:13, FastEthernet0/1
R3(config-router)#
R3(config-router)#do
ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/16/36 ms
R3(config-router)#do
ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout
is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/31/64 ms
R3(config-router)#
·
Let me add ipv6
addresses to loop0 interfaces on all 3 routers:
R1(config)#ipv6 unicast-routing
R1(config)#int loop0
R1(config-if)#ipv6 address 2002:0101:0101:1::1/64
R1(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R1’s ipv4 loopback0
address, 1.1.1.1 in hex format is 0101:0101
R2(config-router)#ipv6 unicast-routing
R2(config)#int loop0
R2(config-if)#ipv6 address 2002:0202:0202:1::2/64
R2(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R2’s ipv4 loopback0
address, 2.2.2.2 in hex format is 0202:0202
R3(config-router)#ipv6 unicast-routing
R3(config)#int loop0
R3(config-if)#ipv6 address 2002:0303:0303:1::3/64
R3(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R3’s ipv4 loopback0
address, 3.3.3.3 in hex format 0303:0303
·
Now, let me create
6to4 tunnels to reach these newly added ipv6 interfaces:
R1(config)#int
tun 1
R1(config-if)#ipv6 address 2002:0101:0101::1/64
R1(config-if)#tunnel source 1.1.1.1
R1(config-if)#tunnel mode ipv6ip 6to4
R1(config-if)#
*Mar 1
00:39:43.359: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel1, changed
state to up
R1(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R1’s ipv4 loopback0
address, 1.1.1.1 in hex format is 0101:0101
R2(config-if)#int
tun1
R2(config-if)#ipv6 address 2002:0202:0202::2/64
R2(config-if)#tunnel source 2.2.2.2
R2(config-if)#tunnel mode ipv6ip 6to4
R2(config-if)#
*Mar 1
00:35:18.535: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel1, changed
state to up
R2(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R2’s ipv4 loopback0
address, 2.2.2.2 in hex format is 0202:0202
R3(config)#int
tun1
R3(config-if)#ipv6 address 2002:0303:0303::3/64
R3(config-if)#tunnel source 3.3.3.3
R3(config-if)#tunnel mode ipv6ip 6to4
R3(config-if)#
*Mar 1
00:36:05.791: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel1, changed
state to up
R3(config-if)#
Observation:
·
ipv6
address is determined as follows, 2002 followed by HEX of R3’s ipv4 loopback0
address, 3.3.3.3 in hex format 0303:0303
·
Now, let me create
default route pointing towards tunnel interface:
R1(config)#ipv6 route 2002::/16 tun1
R1(config)#
R2(config)#ipv6 route 2002::/16 tun1
R2(config)#
R3(config)#ipv6 route 2002::/16 tun1
R3(config)#
·
Now, let me check
the connectivity:
R1(config)#do ping 2002:0202:0202::2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:202:202::2,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/25/44 ms
R1(config)#do ping 2002:0202:0202:1::2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:202:202:1::2,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 0/18/52 ms
R1(config)#do ping 2002:0303:0303::3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:303:303::3,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/33/76 ms
R1(config)#do ping 2002:0303:0303:1::3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:303:303:1::3,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/30/48 ms
R1(config)#
Observation:
·
R1
is able to ping R2’s tunnel interface and loopback0 interface
·
R1
is able to ping R3’s tunnel interface and loopback0 interface
R2(config)#do
ping 2002:0101:0101::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:101:101::1,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 0/20/52 ms
R2(config)#do ping 2002:0101:0101:1::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:101:101:1::1,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/23/76 ms
R2(config)#do ping 2002:0303:0303::3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:303:303::3,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/27/72 ms
R2(config)#do ping 2002:0303:0303:1::3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:303:303:1::3,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/17/52 ms
R2(config)#
Observation:
·
R2
is able to ping R1’s tunnel interface and loopback0 interface
·
R2
is able to ping R3’s tunnel interface and loopback0 interface
R3(config)#do
ping 2002:0101:0101::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:101:101::1,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/32/84 ms
R3(config)#do ping 2002:0101:0101:1::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:101:101:1::1,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 8/26/64 ms
R3(config)#do ping
2002:0202:0202::2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:202:202::2,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/24/76 ms
R3(config)#do ping 2002:0202:0202:1::2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2002:202:202:1::2,
timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip
min/avg/max = 4/26/64 ms
R3(config)#
Observation:
·
R3
is able to ping R1’s tunnel interface and loopback0 interface
·
R3
is able to ping R2’s tunnel interface and loopback0 interface
