CIDR notation changed in firewall->tools->IP access rules?

I was always able to enter in the IP access rules of the fw an IPv6 CIDR /64 range like this


but now I get the message:
‘Only an IPv4 range (CIDR) value of /16 /24 is allowed for IP Access Rule’
Has something changed?

Same exact issue here. Used to work, now doesn’t and I’ve seen no announcement or such indication why. Anyone have any input on this?

Have always been able to employ CIDR in IPv6 with /32 or /64.

Now I get this: ‘Only an IPv4 range (CIDR) value of /16 /24 is allowed for IP Access Rule’

This is REALLY throwing a wrench in the gears here. Anyone else seeing this?

May I suggest to try out creating a Firewall Rule with the needed action (allow, block, bypass, challenge …) the needed IP, IPs or an IP range?

Certainly an option but so limited in quantity on free account.

Just tried that and got “Filter parsing error (1:13): (ip.src in {2601:2c4:c980:b60:b02f:99f4:f4f8:65ad/64}) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ host part of address was not zero”

2601:02C4:C980:0B60::/64 or 2601:02C4:C980:0B60:0000:0000:0000:0000/64 works fine.

Was able to save the rule but it will not deploy. No error message… just won’t deploy.

Clearly it’s supposed to work, as even the Help window below it says so. Have you opened a ticket with Support? If so, please post the ticket # here to get some more eyes on it.

Cloudflare accepts the following CIDR notations: /16 and /24 for IPv4 addresses and /64, /48, and /32 for IPv6

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Have not opened ticket yet. Was hoping this was something others had also seen. Will post ticket# here when I do.

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I have opened a ticket. Let’s wait and see.
([Cloudflare Support] 2242682 - Can’t enter a IPv6 CIDR /64 range in the IP access rules anymore?)

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You could try with Firewall Rules instead.

Hi there,

Sorry for all your trouble here.

We have escalated this issue to our Engineering team.

In the meantime, you could use Firewall Rules to create IPv6 rules as a workaround.

We will keep this post updated as soon as we hear from our Engineering team.


Thanks for the suggestion, but that option has limits and not the option to add comments.

Hi @alfa,

Sorry for the inconvenience this may have caused.

Please bear with us until our Engineer team have identified the root cause and fixed the issue.


The CIDR /64 notation seems to be working here again in the IP access rules secion.

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Working here for several days now.

Thanks to the CloudFlare team and all interested in this thread.

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