I have this problem with a 3640 router.
I've configured a vpn peer with command:
crypto isakmp key 0 <key> <address>
but router save this command in startup-config without the zero
crypto isakmp key <key> <address>
so when I reload it, ios can't insert this line into configuration
Is there any way to solve this problem?
I've tested many ios releases.
My "workaround" now is to configure password encryption aes, so ios save crypto isakmp key with a 6 before the encrypted key.
Is the only solution?
Thanks in advance.