Cisco Switch Documentation
This page includes links to relevant articles on this and other sites related to switches.
- Cisco 2900XL/3500XL, 2940, 2950/2955, 2960, 2970, 3550, 3560, and 3750 Series Switch Password Recovery Procedure
Enabling Dual Stack IPv4/IPv6
Older Cisco switches may not ship with IPv6 enabled. Enabling IPv6 must be done at least once on each switch by changing the Switch Database Management (SDM) Template. Doing this will change the number of addresses the switch can hold in memory as memory will be divided into IPv4 and IPv6 ranges and IPv6 addresses require more memory to store.
- You can view the current SDM template and memory configuration using the show sdm prefer command.
- You can view how the memory allocation will change if you switch the SDM template with the show sdm prefer [default | dual-ipv4-and-ipv6 default | lanbase-routing | qos] command (specify the template you are considering changing to).
Changing the template to allow IPv4/IPv6 dual stack (requires switch be rebooted, save your config first!):
- switch# configure terminal
- switch(config)# sdm prefer dual-ipv4-and-ipv6 default
- switch(config)# end
- switch# reload
The change will be applied once the switch is rebooted.
- switch# erase startup-config This will delete startup configurations if they were saved.
- switch# delete flash:vlan.dat This deletes the vlan configuration.
- switch# reload This must be done last to reload the default configurations.