What is a Room Server?

What is a MeshCore Room Server?
A Room Server is a store-and-forward bulletin board that runs directly on a LoRa node running MeshCore firmware. It acts as a shared message board for the mesh community - any node that can reach the room server can post and read messages without needing internet access or a central server. The whole point of a room server (versus an ordinary channel) is that it retains message history: roaming users who were out of range can come back later and pull the messages they missed, much like an email server.
Key Characteristics
 
Storage: The room server retains message history and pushes it to clients when they connect - a client receives the previous 32 unseen messages on login. (Persistence across a reboot/power cycle depends on your firmware and hardware; do not assume messages survive a power loss without verifying on your firmware version.)
 
Access control: Two passwords - an admin password and a guest password - plus a per-companion ACL (
setperm <pubkey> <level>, with levels Guest / Read-only / Read-write / Admin) and a separate 
set allow.read.only flag for unauthenticated read access.
 
Repeater hybrid: A room server can also be configured as a repeater with 
set repeat on, but this is a trade-off - room servers benefit from an indoor location for USB/Bluetooth administration, whereas repeaters perform best with a high external antenna.
 
Radio requirements: The room server's radio preset (frequency/bandwidth/spreading factor/coding rate) must match the rest of the network; otherwise its packets and adverts cannot be received by other nodes.
Access Control
MeshCore room servers use two passwords plus a per-companion ACL - not a single "three-tier" password ladder:
 
Mechanism
Default
Permissions
 
 
Admin password
password
Full control: manage permissions, delete messages, change all settings
 
Guest password
hello
Read and write messages once authenticated as a guest
 
Per-companion ACL (
setperm)
per node
Levels: Guest / Read-only / Read-write / Admin
 
set allow.read.only flag
off
When enabled, allows unauthenticated read-only access; off by default (no automatic no-password read)
 
Warning: Both default passwords must be changed immediately after first login. The default admin password 
password and guest password 
hello are publicly known.
Why Room Servers Matter
Room servers enable asynchronous community communication entirely over the mesh. A traveler passing through can read recent area messages, a neighborhood can coordinate during a power outage, or volunteers can leave notes for the next person who checks in - all without any internet connection or cellular infrastructure. Because the server stores and re-pushes missed messages, participants do not all need to be in range at the same time.