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fix: bypass Squid for network gateway to fix MCP SSE crash #553

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Merged
Mossaka merged 2 commits into from
Feb 6, 2026
Merged

fix: bypass Squid for network gateway to fix MCP SSE crash #553

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b44a154
fix: bypass Squid for network gateway to fix MCP SSE crash
Mossaka Feb 6, 2026
1e852c7
fix: restrict network gateway bypass to TCP port 80 only
Mossaka Feb 6, 2026
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11 changes: 11 additions & 0 deletions containers/agent/setup-iptables.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,17 @@ if [ -n "$AWF_ENABLE_HOST_ACCESS" ]; then
else
echo "[iptables] WARNING: host.docker.internal could not be resolved, skipping host gateway bypass"
fi

# Also bypass Squid for the container's default network gateway.
# Codex resolves host.docker.internal to this IP (172.30.0.1 on the AWF network)
# instead of the Docker bridge gateway (172.17.0.1). Without this bypass,
# MCP Streamable HTTP traffic goes through Squid, which crashes on SSE connections.
NETWORK_GATEWAY_IP=$(route -n | awk '/^0\.0\.0\.0/ { print $2; exit }')
if [ -n "$NETWORK_GATEWAY_IP" ] && [ "$NETWORK_GATEWAY_IP" != "$HOST_GATEWAY_IP" ]; then
echo "[iptables] Allow direct traffic to network gateway (${NETWORK_GATEWAY_IP}) - bypassing Squid..."
iptables -t nat -A OUTPUT -d "$NETWORK_GATEWAY_IP" -j RETURN
iptables -A OUTPUT -p tcp -d "$NETWORK_GATEWAY_IP" --dport 80 -j ACCEPT
fi
fi

# Block dangerous ports at NAT level (defense-in-depth with Squid ACL filtering)
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