diff --git a/package.json b/package.json
index 5e10614c..38803915 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "author": "Calvin Montgomery",
   "name": "CyTube",
   "description": "Online media synchronizer and chat",
-  "version": "3.51.5",
+  "version": "3.51.6",
   "repository": {
     "url": "http://github.com/calzoneman/sync"
   },
diff --git a/src/io/ioserver.js b/src/io/ioserver.js
index 9058f864..6a7a66c3 100644
--- a/src/io/ioserver.js
+++ b/src/io/ioserver.js
@@ -21,7 +21,19 @@ import http from 'http';
 
 const LOGGER = require('@calzoneman/jsli')('ioserver');
 
-// WIP, not in use yet
+const rateLimitExceeded = new Counter({
+    name: 'cytube_socketio_rate_limited_total',
+    help: 'Number of socket.io connections rejected due to exceeding rate limit'
+});
+const connLimitExceeded = new Counter({
+    name: 'cytube_socketio_conn_limited_total',
+    help: 'Number of socket.io connections rejected due to exceeding conn limit'
+});
+const authFailureCount = new Counter({
+    name: 'cytube_socketio_auth_error_total',
+    help: 'Number of failed authentications from session middleware'
+});
+
 class IOServer {
     constructor(options = {
         proxyTrustFn: proxyaddr.compile('127.0.0.1')
@@ -65,6 +77,7 @@ class IOServer {
 
         const bucket = this.ipThrottle.get(socket.context.ipAddress);
         if (bucket.throttle()) {
+            rateLimitExceeded.inc(1);
             LOGGER.info('Rejecting %s - exceeded connection rate limit',
                     socket.context.ipAddress);
             next(new Error('Rate limit exceeded'));
@@ -74,6 +87,8 @@ class IOServer {
         next();
     }
 
+    /*
+        TODO: see https://github.com/calzoneman/sync/issues/724
     ipConnectionLimitMiddleware(socket, next) {
         const ip = socket.context.ipAddress;
         const count = this.ipCount.get(ip) || 0;
@@ -84,12 +99,45 @@ class IOServer {
         }
 
         this.ipCount.set(ip, count + 1);
+        console.log(ip, this.ipCount.get(ip));
         socket.once('disconnect', () => {
+            console.log('Disconnect event has fired for', socket.id);
             this.ipCount.set(ip, this.ipCount.get(ip) - 1);
         });
 
         next();
     }
+    */
+
+    checkIPLimit(socket) {
+        const ip = socket.context.ipAddress;
+        const count = this.ipCount.get(ip) || 0;
+        if (count >= Config.get('io.ip-connection-limit')) {
+            connLimitExceeded.inc(1);
+            LOGGER.info(
+                'Rejecting %s - exceeded connection count limit',
+                ip
+            );
+            socket.emit('kick', {
+                reason: 'Too many connections from your IP address'
+            });
+            socket.disconnect(true);
+            return false;
+        }
+
+        this.ipCount.set(ip, count + 1);
+        socket.once('disconnect', () => {
+            const newCount = (this.ipCount.get(ip) || 1) - 1;
+
+            if (newCount === 0) {
+                this.ipCount.delete(ip);
+            } else {
+                this.ipCount.set(ip, newCount);
+            }
+        });
+
+        return true;
+    }
 
     // Parse cookies
     cookieParsingMiddleware(socket, next) {
@@ -132,6 +180,7 @@ class IOServer {
             promises.push(verifySession(auth).then(user => {
                 socket.context.user = Object.assign({}, user);
             }).catch(error => {
+                authFailureCount.inc(1);
                 LOGGER.warn('Unable to verify session for %s - ignoring auth',
                         socket.context.ipAddress);
             }));
@@ -153,6 +202,12 @@ class IOServer {
     }
 
     handleConnection(socket) {
+        // TODO: move out of handleConnection if possible
+        // see: https://github.com/calzoneman/sync/issues/724
+        if (!this.checkIPLimit(socket)) {
+            return;
+        }
+
         LOGGER.info('Accepted socket from %s', socket.context.ipAddress);
         counters.add('socket.io:accept', 1);
         socket.once('disconnect', () => counters.add('socket.io:disconnect', 1));
@@ -176,7 +231,7 @@ class IOServer {
         io.use(this.ipProxyMiddleware.bind(this));
         io.use(this.ipBanMiddleware.bind(this));
         io.use(this.ipThrottleMiddleware.bind(this));
-        io.use(this.ipConnectionLimitMiddleware.bind(this));
+        //io.use(this.ipConnectionLimitMiddleware.bind(this));
         io.use(this.cookieParsingMiddleware.bind(this));
         io.use(this.ipSessionCookieMiddleware.bind(this));
         io.use(this.authUserMiddleware.bind(this));
@@ -209,12 +264,12 @@ function patchSocketMetrics() {
 
     Socket.prototype.onevent = function patchedOnevent() {
         onevent.apply(this, arguments);
-        incomingEventCount.inc(1, new Date());
+        incomingEventCount.inc(1);
     };
 
     Socket.prototype.packet = function patchedPacket() {
         packet.apply(this, arguments);
-        outgoingPacketCount.inc(1, new Date());
+        outgoingPacketCount.inc(1);
     };
 }
 
@@ -278,7 +333,7 @@ function emitMetrics(sock) {
         let closed = false;
         let transportName = sock.client.conn.transport.name;
         promSocketCount.inc({ transport: transportName });
-        promSocketAccept.inc(1, new Date());
+        promSocketAccept.inc(1);
 
         sock.client.conn.on('upgrade', newTransport => {
             try {
@@ -298,7 +353,7 @@ function emitMetrics(sock) {
             try {
                 closed = true;
                 promSocketCount.dec({ transport: transportName });
-                promSocketDisconnect.inc(1, new Date());
+                promSocketDisconnect.inc(1);
             } catch (error) {
                 LOGGER.error('Error emitting disconnect metrics for socket (ip=%s): %s',
                         sock.context.ipAddress, error.stack);
diff --git a/www/js/callbacks.js b/www/js/callbacks.js
index 3329acea..02d05b61 100644
--- a/www/js/callbacks.js
+++ b/www/js/callbacks.js
@@ -37,7 +37,7 @@ Callbacks = {
 
     // Socket.IO error callback
     error: function (msg) {
-        window.SOCKET_ERROR_REASON = reason;
+        window.SOCKET_ERROR_REASON = msg;
         $("<div/>")
             .addClass("server-msg-disconnect")
             .text("Unable to connect: " + msg)