Hello Andy
I went into one of my production ISR 4331 routers and created an IPv6 DHCP pool called “laz”.
I attempted to change the information refresh infinite command, and I was able to do so:
R1(config)#ipv6 dhcp pool laz
R1(config-dhcpv6)#information refresh infinite
R1(config-dhcpv6)#exit
R1(config)#exit
R1#show ipv6 dhcp pool
DHCPv6 pool: laz
Information refresh: 4294967295
Active clients: 0
R1#
You can see that the information refresh is set to 4294967295. The value for the refresh time interval is represented by a 32-bit value. According to RFC 8415, when this 32-bit number is set to all ones, the value is interpreted as infinity. This means that the information refresh value of 4294967295, which is 2^32 which is indeed the decimal number that corresponds to a 32-bit number of all ones, thus it means infinity.
What do you see on your device that indicates that this configuration doesn’t change the DHCPv6 behavior? Let us know so that we can further help you in your troubleshooting procedures.
I hope this has been helpful!
Laz