The task was to join two network segments so hosts could communicate directly through a layer-2 bridge. Claude Sonnet 5 created a working bridge with live commands. Restarting the forwarding machine removed it, and manual reconstruction restored connectivity.
The agent used administrative shell access.
A SONiC host joined two Ubuntu clients
Transparent layer-2 bridge task prompt (verbatim):
`node2` and `node3` are attached to two different segments of `node1`. Join those segments into a single layer-2 domain, so the two hosts share one subnet and reach each other directly with `node1` forwarding frames rather than standing in the path as a routed hop.
Node1 ran SONiC on Debian 13 and connected the two client segments through eth1 and eth2. Node2 and node3 ran Ubuntu 24.04.3. A separate management network let the agent run commands on all three machines.
The initial interface listing contained no br0. The agent created it using ip link, attached eth1 and eth2, and brought all three interfaces up. The clients used 192.168.50.0/24. Learned MAC addresses and TTL-preserving pings supported actual layer-2 forwarding. (Bridge creation · Bridge address and forwarding database)
Restart removed the live bridge
The lab also required a restart check. The agent rebooted node1 after the forwarding test.
After node1 rebooted, its listing showed no br0 and eth1 and eth2 were down. There was no saved bridge setup to recreate the bridge automatically. (Node1 immediately after reboot)
The agent then recreated br0 and its member links manually. A four-packet ping succeeded, and the forwarding database again learned the client MAC addresses on different ports. (Manual reconstruction · Four successful replies after repair)
The final ping followed intervention
The bridge forwarded traffic when it existed. Reboot removed it, and the final successful ping followed the agent’s commands to recreate it.
The setup therefore depended on manual reconstruction after a restart. Until those commands ran, node1 had no bridge joining the client segments.
Original run records
transparent-l2-bridge-bash-ubuntu24-5469
instruction.md · Agent configuration · Command record · Evaluation · Host observations
Revised: . Run dates: 5 September 2026.