Is there an existing issue for this?

• I have searched the existing issues

Version

equal or higher than v1.16.0 and lower than v1.17.0

What happened?

When running cilium connectivity test there is the assumption that the user can reach 1.1.1.1 which isn't the case in IPv6-only deployments, and as it is an IP, even with NAT64.

I did also try cilium connectivity test --external-ip "2606:4700:4700::1111" --external-other-ip "2606:4700:4700::1001" --external-cidr "2606:4700:4700::/48", but it parses the last segment of IPv6 address to ports (putting them in square brackets straight up crashes it, and specifying a port like 2606:4700:4700::1111:443 after seems to work-ish but is surprising and non-obvious, and seems to still cause the tests to fail).

How can we reproduce the issue?

• Install with IPv6 connectivity only.
• Run cilium connectivity test

Cilium Version

1.16.2

Kernel Version

6.8.0-47-generic

Kubernetes Version

v1.30.5+k3s1

Regression

No response

Sysdump

N/a

Relevant log output

N/a

Anything else?

No response

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