exo set_rdma_network_config.sh network setup script

Facts

• `tmp/set_rdma_network_config.sh` is a bash script in the exo repository (strict mode `set -euo pipefail`) that rebuilds a Mac's network configuration so every Thunderbolt RDMA port has its own network service on DHCP. exo bundles the same script in the macOS app. [source]
• Step 1, remove the bridge at run time: if `bridge0` exists it removes each member with `ifconfig bridge0 deletem` and then `ifconfig bridge0 destroy`. Errors are ignored. [source]
• Step 2, remove the bridge from stored configuration: `PlistBuddy -c "Delete :VirtualNetworkInterfaces:Bridge:bridge0"` on `/Library/Preferences/SystemConfiguration/preferences.plist`, so it does not come back after reboot. [source]
• Step 3, create and switch to a network location named `exo` (`networksetup -createlocation exo` if none exists, then `-switchtolocation exo`). The script therefore changes the active network location, not just one service. [source]
• Step 4, loop over `networksetup -listallhardwareports`: names starting "Ethernet Adapter" and the "Thunderbolt Bridge" port are skipped; every other port named "Thunderbolt ..." gets a new service called `EXO <port name>` created with `-createnetworkservice` and set to DHCP with `-setdhcp`. [source]
• Step 4 also recreates a service for every other hardware port (Wi-Fi and so on) under its own name if the new location lacks one, because a new location starts empty. [source]
• Step 5, if a "Thunderbolt Bridge" service exists, it is disabled with `-setnetworkserviceenabled "Thunderbolt Bridge" off`. [source]
• The script is idempotent on re-run: existing locations and `EXO ...` services are detected with `grep -q` before creation. [source]
• The script needs root, since it edits the system preferences plist and network services, but contains no `sudo`; the caller must supply it. [source]
• The script sets DHCP only. It never assigns a static address and never calls `route`, so its result is dynamic link-local per port, not the static schemes in static-link-local-ipv4-per-thunderbolt-port-for.md. [source]
• A maintainer replied in issue 1390 (February 2026) that after macOS 26.2 the RDMA interfaces no longer self-assign addresses, that a script in `tmp/` does the setup automatically, and that it "is a little destructive to existing networking settings". [source]
• The issue's summary lists three actions as "essentially what our script does": delete the Thunderbolt bridge, assign a new network service to each Thunderbolt port, enable DHCP or IPv6 auto-assignment. [source]
• A reporter ran the script, rebooted, re-pulled from source and got a working cluster, and proposed README troubleshooting text that warns the script "can be destructive to existing networking configurations". [source]
• The exo README tells source users to run the script and says it "will disable Thunderbolt Bridge and set dhcp on each RDMA port" (caveat 4 of the RDMA section). The same list requires every node connected to every other node, TB5 cables, avoiding the port next to Ethernet on a Mac Studio, and exactly matching macOS versions. [source]
• Side effects outside RDMA: the Mac is switched to a new `exo` location, so previously configured per-service settings (static IPs, DNS, proxies, VPN services) from the old location are not carried over. This is the mechanism behind the "destructive" warning. [source]
• The 4-node M3 Ultra cluster in exo issue 1847 ran in network location `exo` with Thunderbolt Bridge disabled and `EXO Thunderbolt 1-6` services on DHCP link-local, which matches the script's output. [source]
• Symptom without the setup: loading a model with Tensor sharding and the `MLX RDMA` instance type shows `preparing` then `failed` in the dashboard and repeats `Worker plan: CreateRunner` in the console. [source]
• The script does not touch `rdma_ctl` or recovery-mode RDMA enabling; those stay manual steps before it. [source]
• Scope. The maintainer's phrase "essentially what our script does" lists three steps; the script does more (it creates a location, recreates all other services, edits the preferences plist). The summary understates the side effects. [source]
• DHCP versus static: see static-link-local-ipv4-per-thunderbolt-port-for.md; this script takes the DHCP side. [source]
• Whether the DHCP link-local result survives a macOS 27 upgrade and the reworked RDMA library. [source]
• Whether the script is still needed once the bundled app sets up the network itself. The sources say the app "bundles" the script, not how it runs it. [source]
• `tmp/set_rdma_network_config.sh` destroys `bridge0` at run time and deletes its entry from the system preferences plist with PlistBuddy. [source]
• The script creates and switches to a network location named `exo`. [source]
• For each Thunderbolt hardware port other than "Thunderbolt Bridge" the script creates a service named `EXO <port>` and sets it to DHCP. [source]
• The script re-creates a service for every non-Thunderbolt, non-"Ethernet Adapter" hardware port in the new location and disables the "Thunderbolt Bridge" service. [source]
• The script assigns no static address and no routes. [source]
• The exo README says source users must run the script, and that it disables Thunderbolt Bridge and sets DHCP on each RDMA port. [source]
• A maintainer calls the script "a little destructive to existing networking settings" and ties the need to macOS 26.2 no longer self-assigning addresses on the RDMA interfaces. [source]
• Without the network setup, loading a Tensor-sharded `MLX RDMA` instance cycles between `preparing` and `failed`. [source]
• The README RDMA caveats also require OS versions to match exactly, including beta numbers, on all devices. [source]