Set SNMP scanner default timings to 10m/5s

A typical router keeps active devices' ARP entries fresh continuously,
so a 10-minute poll interval stays well within common ARP cache TTLs
while keeping device-event churn modest (each poll records a DeviceSeen
event per device). A 5s per-request timeout adds margin for a busy
agent or large ARP table at no cost on the happy path.

Updates the default in settings.rs and the sample TOML, README and
NixOS module. TODO timing-review item narrowed to the ARP scanner.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -148,8 +148,8 @@ If you are using Docker I recommend writing the config using TOML, [here](https:
 |`snmp_scanner.enabled`|`true` when the section is present, otherwise off|Whether to run the SNMP scanner. The whole `[snmp_scanner]` section is optional and the scanner stays off unless you add it; within the section it defaults to enabled.|
 |`snmp_scanner.target`||SNMP agent to poll, as `host:port` (e.g. your gateway: `192.168.1.1:161`). The scanner reads the agent's ARP table over SNMPv2c — no local probing.|
 |`snmp_scanner.community`||SNMPv2c read-only community string. Use a read-only community and never commit a real secret.|
-|`snmp_scanner.wait_between_scans`|`2m`|Time to wait between polls. Keep it well under the agent's ARP cache timeout so active devices aren't missed.|
-|`snmp_scanner.timeout`|`3s`|Per-poll SNMP request timeout.|
+|`snmp_scanner.wait_between_scans`|`10m`|Time to wait between polls. Keep it well under the agent's ARP cache timeout so active devices aren't missed.|
+|`snmp_scanner.timeout`|`5s`|Per-poll SNMP request timeout.|
 |`notifications.method`|`pushover`|For now just pushover, you can set this to "none" to avoid sending notifications (it will just log)|
 |`notifications.notify_when_not_seen_for`|`1w`|Send a notification if a device comes back online after not being seen for this timeframe (you can use hours, weeks, etc.)|
 |`notifications.pushover.token`||Your pushover token goes here, just copy&paste from their website after creating the app|

TODO.md

@@ -10,7 +10,7 @@
 - [x] Add configuration options to enable/disable each scanner
 - [ ] Implement the pushover API call directly to support HTML content and review notification text to use it
 - [ ] Add "devices seen on last scan" to the ARP and SNMP scanners status
-- [ ] Review the recommended timings for ARP and SNMP scanners (change defaults)
+- [ ] Review the recommended timings for the ARP scanner (change defaults) — SNMP defaults set to 10m/5s
 
 ## Frontend
 

backend/src/settings.rs

@@ -98,8 +98,8 @@ impl Default for SnmpScanner {
             enabled: false,
             target: String::new(),
             community: String::new(),
-            wait_between_scans: DurationString::try_from("2m".to_string()).unwrap(),
-            timeout: DurationString::try_from("3s".to_string()).unwrap(),
+            wait_between_scans: DurationString::try_from("10m".to_string()).unwrap(),
+            timeout: DurationString::try_from("5s".to_string()).unwrap(),
         }
     }
 }

examples/sample_oott.toml

@@ -28,8 +28,8 @@ enabled=true # Set to false to disable the DHCP scanner
 # enabled=true # Set to false to disable the SNMP scanner without removing this section
 # target="192.168.1.1:161" # SNMP agent to poll, as host:port. Point this at your gateway (router/firewall).
 # community="public" # SNMPv2c read-only community string. Use a read-only community; never commit a real secret here.
-# wait_between_scans="2m" # Wait time between polls. Keep this well under the agent's ARP cache timeout so active devices aren't missed.
-# timeout="3s" # Per-poll SNMP request timeout.
+# wait_between_scans="10m" # Wait time between polls. Keep this well under the agent's ARP cache timeout so active devices aren't missed.
+# timeout="5s" # Per-poll SNMP request timeout.
 # Note: SNMP must be enabled on the target. On pfSense: Services > SNMP (v2c; the mibII module exposes the ARP table).
 # On OPNsense: install the os-net-snmp plugin, then Services > Net-SNMP. In both cases add a firewall rule allowing
 # UDP/161 from the host running OOTT.

nix/modules/oott-service.nix

@@ -94,12 +94,12 @@ in {
     snmp_scanner.wait_between_scans = mkOption {
       type = types.str;
       description = "Wait time between SNMP polls. Keep it well under the agent's ARP cache timeout so active devices aren't missed.";
-      default = "2m";
+      default = "10m";
     };
     snmp_scanner.timeout = mkOption {
       type = types.str;
       description = "Per-poll SNMP request timeout.";
-      default = "3s";
+      default = "5s";
     };
     notifications.method = mkOption {
       type = types.str;