diff --git a/logging/alloy-config.alloy b/logging/alloy-config.alloy
index 8d9dec5..88c068a 100644
--- a/logging/alloy-config.alloy
+++ b/logging/alloy-config.alloy
@@ -29,10 +29,17 @@ loki.relabel "syslog" {
   }
 }
 
+// syslog_format is "rfc3164" (legacy BSD syslog, no version field) rather
+// than the component's rfc5424 default — confirmed by packet capture that
+// both the Yealink phones and RouterOS routers send rfc3164 in practice.
+// A listener can only parse one format; if a device ever sends genuine
+// rfc5424, it needs its own listener on a different port.
+
 loki.source.syslog "network_devices_udp" {
   listener {
-    address  = "0.0.0.0:514"
-    protocol = "udp"
+    address       = "0.0.0.0:514"
+    protocol      = "udp"
+    syslog_format = "rfc3164"
     labels = {
       job       = "syslog",
       transport = "udp",
@@ -45,8 +52,9 @@ loki.source.syslog "network_devices_udp" {
 
 loki.source.syslog "network_devices_tcp" {
   listener {
-    address  = "0.0.0.0:1514"
-    protocol = "tcp"
+    address       = "0.0.0.0:1514"
+    protocol      = "tcp"
+    syslog_format = "rfc3164"
     labels = {
       job       = "syslog",
       transport = "tcp",
diff --git a/logging/docker-compose.yaml b/logging/docker-compose.yaml
index fb8e501..c792eda 100644
--- a/logging/docker-compose.yaml
+++ b/logging/docker-compose.yaml
@@ -16,8 +16,10 @@ services:
       - logging-nw
 
   alloy:
-    # Pinned for the same reason as loki — see comment there.
-    image: grafana/alloy:v1.4.3
+    # Pinned for the same reason as loki — see comment there. v1.5.0
+    # specifically (not v1.4.3) because it's the first release with
+    # syslog_format = "rfc3164" support, needed below.
+    image: grafana/alloy:v1.5.0
     container_name: alloy
     command:
       - run