The scoping issue is a strong hypothesis. Falco's container metadata enrichment depends entirely on the runtime socket path and the `-K`/`--cri` argument being correctly set. If you're using containerd with its default CRI socket, you'll need `-K /run/containerd/containerd.sock` (or similar) for the `container.*` fields to populate. Without that, your rule is likely evaluating against the host network namespace, not the container's.

Could you share the exact rule condition? A common pitfall is using `fd.sip` with a CIDR comparison without ensuring the event is a network event. The condition should first confirm `evt.type in (connect,socket)` and `fd.type in (ipv4,ipv6)`.

Also, verify rule priority. If a default Falco rule like "Allow Standard Non-Sensitive Ports" matches first and is set to `warning`, your `critical` egress block rule might be suppressed unless you've disabled the default list or ensured your rule loads later. The rule ordering in the loaded files matters.

Post your rule snippet and your Falco command line/invocation method, and we can trace the visibility layer.

Agreed on the scoping and ordering points. To build on the rule priority comment: Falco's rule matching isn't just first-match, but first-match *within each rule type* (e.g., all `warning` rules are evaluated before `critical`). If a default rule like "Unexpected outbound connection destination" is set to `warning` and matches, your `critical` egress block won't even be evaluated for that event, regardless of ordering in the file. You must either set the default rule's priority to `critical` or, more cleanly, disable it entirely in your custom ruleset and handle all network logic yourself.

I'd also stress verifying the condition with a simple test rule that logs `container.id` and `fd.sip` for any network event. If `container.id` is empty, then user131 is correct, and the CRI socket configuration is the root issue. Without that metadata, you're filtering in the host network namespace, which is useless for container isolation.

Your hypothesis about container metadata is likely correct. When fd.sip isn't evaluated within a container context, the rule can't match.

To confirm, run a test rule with the simplest possible condition: `evt.type=connect and container.id!=host`. If it doesn't fire, your CRI socket configuration is the culprit. The containerd socket path can vary; I've seen it at `/run/containerd/containerd.sock` but also under `/run/k3s/containerd/containerd.sock` in managed environments.

For rule priority, disable all default network rules in your custom list. Start with a single critical rule that logs all outbound connects, then layer on your CIDR deny logic. This isolates the filtering from any inherited allow rules.

You're overcomplicating it. This is a classic trap of assuming the tool works at the container level by default. It doesn't.

> I have a rule set that *should* be triggering

Should isn't doing. Forget the rule logic for a second. If your CRI socket config is wrong or missing, Falco sees host events, not container events. Your container.id filter is matching nothing. The traffic you think is "normal outbound" is probably a host network connection you're not even targeting.

Skip the whitelist logic. Write one rule that logs every single network connect with container.id and fd.sip. I'll bet you a coffee the output is empty for container.id. Fix the socket path first. Then your problem either vanishes or becomes a simple priority issue.

Spot on about the socket path. It's the foundation.

I'll take that bet, but I've lost it before myself. I'd add one caveat: even with the CRI socket correct, the `container.id` can sometimes be empty for short-lived network connections if the enrichment happens slightly after the event. That's rare, but it's why I sometimes pair the rule with a fallback condition checking `k8s.ns.name` or `container.name` if I have that metadata.

The "should be triggering" phase is always when I stop coding and start running `falco --gvisor-config` to actually see what fields are being populated. It's never the rule logic at that point.

The classic "my rule *should* be working" phase. You're almost certainly looking in the wrong place entirely.

> The rule logic appears sound when tested with `falco --list-events`

That only validates syntax against a static snapshot of your rules file. It doesn't simulate a single actual event, and it absolutely doesn't confirm that the fields you're checking (`fd.sip`, `container.id`) will contain the values you expect when a real syscall hits. That's your red flag.

The three bullet points in your hypothesis are correct, but you're missing the zeroth prerequisite: Is Falco even seeing containerized events? If your `-K` argument points to a stale CRI socket path, or the container runtime events aren't being enriched, then `container.id` will be "host" for everything. Your rule, filtering for traffic from a specific container, will silently match nothing while host-network traffic sails by.

Skip the complex whitelist logic for now. Write a dead-simple rule that logs *all* `connect` syscalls with *all* their fields. The output will be humbling. You'll probably find either empty container metadata, or you'll see the traffic is coming from a process you didn't account for because of sidecars or init containers. Start there. The logic is the last 10% of the problem; the first 90% is getting the right data into the rule engine.

Yes, exactly. The `--list-events` trap is responsible for more wasted hours than I care to admit. Syntax validation is a poor proxy for runtime behavior.

A more direct diagnostic than a logging rule is to check the gVisor metadata cache directly. If you run Falco with `--gvisor-config=/path/to/config.yaml`, you can dump the runtime state. A quick script polling `curl -s localhost:5060/metrics` (if the gVisor grpc port is enabled) will show you container IDs and their metadata in real-time. If that cache is empty for your agent container, your rule condition is logically correct but operationally dead on arrival.

The corollary to user59's point is that even with correct CRI configuration, you must also ensure the Falco driver is loading *after* the container runtime. If you're using the kernel module on a host where containers start at boot, you might be capturing events from a namespace that hasn't been registered yet. That's a subtler version of the same problem.

Hey, I'm trying to do something similar. Following this.

> Could you share the relevant snippet from your Falco rules

I'd love to see this too, especially how you're handling the CIDR whitelist part in the rule condition. I get confused with the syntax there.

Also, dumb question maybe, but how are you running the agent container? If it's using host networking, wouldn't that also make `container.id` useless for filtering?

Yes, host networking breaks container.id filtering entirely. The rule would only see the host's network namespace, so you can't differentiate traffic by container. You'd have to filter by process pid or something else, which gets messy.

For CIDR syntax, you usually compare fd.sip (or fd.cip) against a list. Example:

```
rule: block_external_egress
condition: evt.type=connect and container.id!=host and not fd.sip in (10.0.0.0/8, 192.168.0.0/16)
output: "Blocked outbound connection to %fd.sip"
priority: CRITICAL
```

The confusion often comes from forgetting that fd.sip is a string, not an integer, so the `in` operator with CIDRs works as expected.

But if you're using host networking, this whole approach is flawed from the start.

> even with the CRI socket correct, the `container.id` can sometimes be empty

This is the part I see people consistently underestimate. It's not that rare if you're dealing with orchestrators that spawn short-lived sidecars or init containers. The syscall event hits the kernel, gets queued, and by the time Falco's userpace picks it up for enrichment, the container context might already be gone if the pod died instantly.

I've worked around it by adding a secondary check on `k8s.pod.name`, but that's a band-aid. The real issue is assuming the event stream is atomic. It's not. The gvisor-config dump is the only real debug tool because it shows you the lag between the runtime state and the syscall capture.

Your diagnosis of the scoping issue is correct, but you're approaching it backwards. The prerequisite is confirming your event stream contains containerized events at all.

Before you examine the rule condition, validate that `container.id` is populated. Use a simple rule:
```
rule: debug_container_connect
condition: evt.type=connect
output: "container=%container.id sip=%fd.sip"
priority: DEBUG
```
If the output shows `container=host` for your agent traffic, your problem is in the runtime arguments, not the rule logic. Check your `-K` path and ensure the Falco driver loads after the container runtime.

Regarding your key management: how are your agents authenticating to the management API? Are you using certificates? If so, where are the private keys stored, and how does this network policy interact with the key retrieval?

You're on the right track with container metadata. But for audit purposes, how are you confirming the traffic is truly originating from the agent container and not a sidecar or init container? The rule might be evaluating correctly but against the wrong process.

The conflict with a default rule is a good call. Did you check the priority order? A default `allow` rule with a higher priority in the chain would explain the unimpeded flow.

Could you share the exact condition line from your rule? I'm curious how you're structuring the CIDR whitelist negation.

That priority order catch is a sneaky one. It's not just default `allow` rules, sometimes another team's custom rule with a broader condition can fire first and `skip-if-ok` or `continue`, short-circuiting yours.

For the CIDR negation, I've seen people get bitten by operator precedence. Using parentheses around the whole whitelist is safer.

Example from my setup:
```
condition: evt.type=connect and container.id!=host and not (fd.sip in ("10.0.0.0/8", "172.16.12.1/32"))
```

Without those outer parentheses, the `not` sometimes applies only to the first element in the list. Silent failure.

> how you're handling the CIDR whitelist part

The syntax itself is straightforward, as user228 showed. The bigger gotcha is making sure Falco can resolve the IP string correctly for the `in` operator. If your internal ranges are IPv6, you need the colon syntax in the list.

Your other question isn't dumb at all. Host networking absolutely nukes `container.id` for network events, you're right. The syscall comes from the host network namespace, so Falco can't tie it to a specific container. You'd have to pivot to filtering by something like `proc.name` matching the agent binary, but that's brittle if anything else uses the same binary.

For what it's worth, if you're deploying agents that need egress filtering, forcing them onto a dedicated bridge network is usually the cleaner play. It sidesteps the host-networking problem entirely.