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    Are people unaware of ipcalc?

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      I can recommend sipcalc as well.

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        that looks even more appropriate for scripting

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      I’m curious about how this is implemented. It seems to delegate the lifting to some sort of policy engine. The logic seems to be some dsl embedded within the go file: https://github.com/mhausenblas/cidrchk/blob/master/main.go#L20

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        It seems to use the evaluation module from https://github.com/open-policy-agent/opa

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          Seems like an odd dependency. Go’s stdlib has IPNet.Contains.

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        This is nice to see. We need more scripting-friendly IP addressing tools.

        I’ve made https://github.com/vyos/ipaddrcheck for automated extended “validness” checks (like “is it a valid IPv4 network prefix), now I think testing for overlaps can be a good option to add there too.

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          Thanks and also thanks for sharing ipaddrcheck!

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          What I would love is a tool, ideally CLI, that could pull appropriate subnets in sequence from a larger block. For example: “With a netblock of, give me three sequential /24s and a /22” output:

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            You should report contains via an exit code instead of printing out yes/no, so scripts can write:

            if cidrchk contains "$cidr" "$ip" >/dev/null; then

            instead of:

            if cidrchk contains "$cidr" "$ip" | grep -q yes; then

            I’m curious to understand why checks are routed through “rego”: I’m not familiar with rego, but it seems like it adds a lot of code and complexity…

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              Reminds me of the python cidr iterator I wrote back when I was in university