Egress reject audit logging (LOG target before REJECT) #40
Description
Problem
firewall.sh silently rejects outbound traffic that doesn't match the allowlist. There's no record of what was blocked — we can't audit agent network behavior or detect unexpected egress attempts.
Fix
Add an iptables LOG target immediately before the existing REJECT rule in firewall.sh:
_ipt -A OUTPUT -j LOG --log-prefix "CLIDE-REJECT: " --log-level 4
_ipt -A OUTPUT -j REJECT --reject-with icmp-port-unreachableSame for ip6tables.
Logs go to the kernel ring buffer (dmesg / /var/log/kern.log). For structured consumption, a future poller (v5) can tail these and write to egress_events.jsonl.
Size
XS — 15 minute change to firewall.sh.
Notes
- PR Add configurable iptables egress firewall for container network isolation #25 (egress firewall) is already merged. This is a standalone add-on.
- Current rule is
REJECT, notDROP— use prefix "CLIDE-REJECT" for clarity. - Consider rate-limiting the LOG rule (
-m limit --limit 10/min) to prevent log flooding from a looping agent.
Source: workspace/notes/research/clide_monitoring.md, final_observability_ticket_plan.md (C-2)
Reacted by Copilot
Activity
itscooleric commentedon Mar 7, 2026
Copilot implementation note:
The change is entirely in
firewall.sh, section 6 (around line 101). Replace:```bash
6. Reject all other outbound traffic (REJECT gives immediate feedback vs DROP's timeout)
_ipt -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
_ip6 -A OUTPUT -j REJECT
```
With:
```bash
6. Log then reject all other outbound traffic
_ipt -A OUTPUT -m limit --limit 10/min -j LOG --log-prefix "CLIDE-REJECT: " --log-level 4
_ip6 -A OUTPUT -m limit --limit 10/min -j LOG --log-prefix "CLIDE-REJECT: " --log-level 4
_ipt -A OUTPUT -j REJECT --reject-with icmp-port-unreachable
_ip6 -A OUTPUT -j REJECT
```
Notes:
dmesg//var/log/kern.loginside the container."CLIDE-REJECT: "(not CLIDE-DROP — the rule is REJECT).Testing: After applying, run a command that hits a non-allowlisted host (e.g.
curl https://example.com) and verify you see aCLIDE-REJECT:line indmesgoutput.feat: add egress reject audit logging (LOG before REJECT in firewall.sh)
Stage clean: latest code from Gitea (#107)