fix: Parse actual subnet from routing table instead of assuming /24#32856
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anshul-garg27 wants to merge 1 commit intoanthropics:mainfrom
Open
fix: Parse actual subnet from routing table instead of assuming /24#32856anshul-garg27 wants to merge 1 commit intoanthropics:mainfrom
anshul-garg27 wants to merge 1 commit intoanthropics:mainfrom
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The firewall init script hardcodes a /24 subnet mask for the host network, which fails on networks with different subnet configurations (e.g., /16, /20). Parse the actual subnet CIDR from the routing table, with a /24 fallback for compatibility.
This was referenced Mar 11, 2026
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Summary
/24subnet assumption with actual routing table parsing in.devcontainer/init-firewall.shProblem
Line 100:
HOST_NETWORK=$(echo "$HOST_IP" | sed "s/\.[0-9]*$/.0\/24/")assumes the host network is always a /24 subnet. This fails on networks with different configurations (e.g., /16, /20, /28), blocking container-to-host communication.Fix
Parse the actual subnet CIDR from
ip routeoutput using the host IP as a lookup key. Falls back to the original /24 assumption if route parsing fails, maintaining backward compatibility.Test plan
bash -n init-firewall.sh