Manually Configured Tunnels
This adit blazon is point-to-point in nature. Cisco IOS requires statically configuring the
destination addresses of these tunnels. Configuring a chiral IPv6 over IPv4 adit is almost
identical to configuring an IPv4 GRE tunnel; the alone aberration is ambience the adit mode.
Example 20-14 and Figure 20-7 appearance a manually configured tunnel. IPv4 reachability has already
been configured and verified, but is not shown.
Figure 20-7 Manually Configured Tunnel
Table 20-7 Cisco IOS Adit Modes and Destinations
Tunnel Blazon Adit Approach Destination
Manual ipv6ip An IPv4 address
GRE over IPv4 gre ip An IPv4 address
Automatic 6to4 ipv6ip 6to4 Automatically determined
ISATAP ipv6ip isatap Automatically determined
Automatic IPv4-compatible ipv6ip auto-tunnel Automatically determined
Example 20-14 Chiral Adit Configuration
! In this example, Clemens and Ford are active IPv4 and OSPFv2 on their
! loopback 0 interfaces and the articulation that connects the two routers. This provides
! the IPv4 connectivity appropriate for these tunnels to work.
!Configuration on the Ford router:
Ford# appearance run interface tunnel0
interface Tunnel0
no ip address
ipv6 abode 2001:DB8::1:1/64
IPv6 Host IPv6 Host
IPv6 Network
Dual-Stack
Router ‘Ford’
Dual-Stack
Router ‘Clemens’
2001:DB8::1:1/64
2001:DB8::1:2/64
Loopback 0
172.30.30.1
Loopback 0
172.30.20.1
IPv4 Network
Tunnel 0 Adit 0
tunnel antecedent Loopback0
! In the adit destination, 172.30.20.1 is Clemens’s Loopback0 interface:
tunnel destination 172.30.20.1
tunnel approach ipv6ip
Ford#
! Configuration on the Clemens router:
Clemens# appearance run interface tunnel0
interface Tunnel0
no ip address
ipv6 abode 2001:DB8::1:2/64
tunnel antecedent Loopback0
! In the adit destination, 172.30.30.1 is Ford’s Loopback0 interface:
tunnel destination 172.30.30.1
tunnel approach ipv6ip
! Demonstrating reachability beyond the tunnel:
Clemens# ping 2001:DB8::1:1
Type escape arrangement to abort.
Sending 5, 100-byte ICMP Echos to 2001:DB8::1:1, abeyance is 2 seconds:
!!!!!
Success amount is 100 percent (5/5), round-trip min/avg/max = 36/36/40 ms
Clemens#