docker networking ai_generated true

iptables failed: iptables --wait -t nat -A DOCKER

ID: docker/docker-iptables-failed

Also available as: JSON · Markdown
85%Fix Rate
88%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
27 active — — —

Root Cause

Docker failed to set up iptables rules for container networking. Occurs when iptables is locked, rules conflict with existing firewall configurations, or iptables/nftables mismatch.

generic

Workarounds

  1. 88% success Restart the Docker daemon to recreate iptables chains 
    sudo systemctl restart docker — Docker will re-create its iptables chains cleanly

    Sources: https://docs.docker.com/network/packet-filtering-firewalls/

  2. 82% success Switch Docker to nftables backend if the system uses nftables 
    Check if system uses nftables: nft list ruleset. If so, ensure iptables points to iptables-nft: sudo update-alternatives --set iptables /usr/sbin/iptables-nft

    Sources: https://docs.docker.com/network/packet-filtering-firewalls/

Dead Ends

Common approaches that don't work:

  1. Flushing all iptables rules with iptables -F 85% fail

    Deletes all firewall rules including security rules, potentially exposing the host to network attacks

  2. Disabling iptables in Docker with --iptables=false 80% fail

    Containers cannot reach the internet or each other; port publishing stops working entirely

Error Chain

Leads to:
Preceded by:
Frequently confused with: