Allow container SSH through iptables DOCKER-USER chain#100
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Allow container SSH through iptables DOCKER-USER chain#100
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drewmalin
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Mar 10, 2026
v1/providers/shadeform/firewall.go
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| // Allow inbound traffic on the loopback interface. | ||
| ipTablesAllowDockerUserInpboundLoopback = "iptables -A DOCKER-USER -i lo -j ACCEPT" | ||
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| // Allow external inbound to container SSH (dport 22 because Docker DNAT rewrites host:2222 -> container:22). |
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It may be more correct to state that this is opening up any traffic to 22, not just 2222
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@drewmalin We have updated the comment with a more clear scope Can we get a quick review and merge on this PR.
Thanks in Advance!
drewmalin
previously approved these changes
Mar 10, 2026
drewmalin
approved these changes
Mar 12, 2026
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This PR addresses the issue where containers on Shadeform and its sub-providers were unable to build or accept SSH connections due to an iptables rule that dropped inbound traffic to Docker containers.
The change allows traffic to reach container SSH mapped via VM port 2222 → container port 22, while keeping existing protections that block other container ports from the internet.
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