diff --git a/Signal.xcodeproj/project.pbxproj b/Signal.xcodeproj/project.pbxproj
index d81bb1ece..73df8b416 100644
--- a/Signal.xcodeproj/project.pbxproj
+++ b/Signal.xcodeproj/project.pbxproj
@@ -96,7 +96,6 @@
 		346129721FD1D74C00532771 /* SignalKeyingStorage.m in Sources */ = {isa = PBXBuildFile; fileRef = 346129591FD1D74B00532771 /* SignalKeyingStorage.m */; };
 		346129731FD1E01700532771 /* PromiseKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 451DE9F11DC1585F00810E42 /* PromiseKit.framework */; };
 		346129741FD1E02D00532771 /* PromiseKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 451DE9F11DC1585F00810E42 /* PromiseKit.framework */; };
-		346129761FD1E0B500532771 /* WeakTimer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 346129751FD1E0B500532771 /* WeakTimer.swift */; };
 		346129951FD1E30000532771 /* OWSDatabaseMigration.h in Headers */ = {isa = PBXBuildFile; fileRef = 346129931FD1E30000532771 /* OWSDatabaseMigration.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		346129961FD1E30000532771 /* OWSDatabaseMigration.m in Sources */ = {isa = PBXBuildFile; fileRef = 346129941FD1E30000532771 /* OWSDatabaseMigration.m */; };
 		346129991FD1E4DA00532771 /* SignalApp.m in Sources */ = {isa = PBXBuildFile; fileRef = 346129971FD1E4D900532771 /* SignalApp.m */; };
@@ -697,7 +696,6 @@
 		346129571FD1D74B00532771 /* Release.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = Release.m; sourceTree = "<group>"; };
 		346129581FD1D74B00532771 /* SignalKeyingStorage.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SignalKeyingStorage.h; sourceTree = "<group>"; };
 		346129591FD1D74B00532771 /* SignalKeyingStorage.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SignalKeyingStorage.m; sourceTree = "<group>"; };
-		346129751FD1E0B500532771 /* WeakTimer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = WeakTimer.swift; sourceTree = "<group>"; };
 		346129931FD1E30000532771 /* OWSDatabaseMigration.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSDatabaseMigration.h; sourceTree = "<group>"; };
 		346129941FD1E30000532771 /* OWSDatabaseMigration.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSDatabaseMigration.m; sourceTree = "<group>"; };
 		346129971FD1E4D900532771 /* SignalApp.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = SignalApp.m; sourceTree = "<group>"; };
@@ -1461,7 +1459,6 @@
 				B97940251832BD2400BD66CB /* UIUtil.h */,
 				B97940261832BD2400BD66CB /* UIUtil.m */,
 				45F170D51E315310003FC1F2 /* Weak.swift */,
-				346129751FD1E0B500532771 /* WeakTimer.swift */,
 			);
 			path = utils;
 			sourceTree = "<group>";
@@ -3076,7 +3073,6 @@
 				344F249A200FD03300CFB4F4 /* MessageApprovalViewController.swift in Sources */,
 				450998681FD8C0FF00D89EB3 /* AttachmentSharing.m in Sources */,
 				347850711FDAEB17007B8332 /* OWSUserProfile.m in Sources */,
-				346129761FD1E0B500532771 /* WeakTimer.swift in Sources */,
 				346129F81FD5F31400532771 /* OWS100RemoveTSRecipientsMigration.m in Sources */,
 				34074F61203D0CBE004596AE /* OWSSounds.m in Sources */,
 				346129B51FD1F7E800532771 /* OWSProfileManager.m in Sources */,
diff --git a/SignalServiceKit/src/Network/API/TSNetworkManager.m b/SignalServiceKit/src/Network/API/TSNetworkManager.m
index 938f57fa7..75aa68dde 100644
--- a/SignalServiceKit/src/Network/API/TSNetworkManager.m
+++ b/SignalServiceKit/src/Network/API/TSNetworkManager.m
@@ -9,6 +9,7 @@
 #import "TSAccountManager.h"
 #import "TSVerifyCodeRequest.h"
 #import <AFNetworking/AFNetworking.h>
+#import <SignalServiceKit/SignalServiceKit-Swift.h>
 
 NSString *const TSNetworkManagerDomain = @"org.whispersystems.signal.networkManager";
 
@@ -93,6 +94,8 @@ typedef void (^failureBlock)(NSURLSessionDataTask *task, NSError *error);
         }
 
         successBlock(task, responseObject);
+
+        [OutageDetection.sharedManager reportNetworkSuccess];
     };
     TSNetworkManagerFailure failure = [TSNetworkManager errorPrettifyingForFailureBlock:failureBlock request:request];
 
@@ -151,6 +154,9 @@ typedef void (^failureBlock)(NSURLSessionDataTask *task, NSError *error);
 
     return ^(NSURLSessionDataTask *_Nullable task, NSError *_Nonnull networkError) {
       NSInteger statusCode = [task statusCode];
+
+      [OutageDetection.sharedManager reportNetworkFailure];
+
       NSError *error       = [self errorWithHTTPCode:statusCode
                                    description:nil
                                  failureReason:nil
diff --git a/SignalServiceKit/src/Network/OutageDetection.swift b/SignalServiceKit/src/Network/OutageDetection.swift
new file mode 100644
index 000000000..e645c6b43
--- /dev/null
+++ b/SignalServiceKit/src/Network/OutageDetection.swift
@@ -0,0 +1,110 @@
+//
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
+//
+
+import Foundation
+import os
+
+@objc
+public class OutageDetection: NSObject {
+    @objc(sharedManager)
+    public static let shared = OutageDetection()
+
+    // These properties should only be accessed on the main thread.
+    private var hasOutage = false {
+        didSet {
+            SwiftAssertIsOnMainThread(#function)
+        }
+    }
+    private var mayHaveOutage = false {
+        didSet {
+            SwiftAssertIsOnMainThread(#function)
+
+            ensureCheckTimer()
+        }
+    }
+
+    private func checkForOutageSync() -> Bool {
+        let host = CFHostCreateWithName(nil, "uptime.signal.org" as CFString).takeRetainedValue()
+        CFHostStartInfoResolution(host, .addresses, nil)
+        var success: DarwinBoolean = false
+        guard let addresses = CFHostGetAddressing(host, &success)?.takeUnretainedValue() as NSArray? else {
+            Logger.error("\(logTag) CFHostGetAddressing failed: no addresses.")
+            return false
+        }
+        guard success.boolValue else {
+            Logger.error("\(logTag) CFHostGetAddressing failed.")
+            return false
+        }
+        var isOutageDetected = false
+        for case let address as NSData in addresses {
+            var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
+            if getnameinfo(address.bytes.assumingMemoryBound(to: sockaddr.self), socklen_t(address.length),
+                           &hostname, socklen_t(hostname.count), nil, 0, NI_NUMERICHOST) == 0 {
+                let addressString = String(cString: hostname)
+                if addressString != "127.0.0.1" {
+                    Logger.verbose("\(logTag) addressString: \(addressString)")
+                    isOutageDetected = true
+                }
+            }
+        }
+        return isOutageDetected
+    }
+
+    private func checkForOutageAsync() {
+        DispatchQueue.global().async {
+            let isOutageDetected = self.checkForOutageSync()
+            DispatchQueue.main.async {
+                self.hasOutage = isOutageDetected
+            }
+        }
+    }
+
+    private var checkTimer: Timer?
+    private func ensureCheckTimer() {
+        // Only monitor for outages in the main app.
+        guard CurrentAppContext().isMainApp else {
+            return
+        }
+
+        if mayHaveOutage {
+            if checkTimer != nil {
+                // Already has timer.
+                return
+            }
+
+            // The TTL of the DNS record is 60 seconds.
+            checkTimer = WeakTimer.scheduledTimer(timeInterval: 60, target: self, userInfo: nil, repeats: true) { [weak self] _ in
+                SwiftAssertIsOnMainThread(#function)
+
+                guard CurrentAppContext().isMainAppAndActive else {
+                    return
+                }
+
+                guard let strongSelf = self else {
+                    return
+                }
+
+                strongSelf.checkForOutageAsync()
+            }
+        } else {
+            checkTimer?.invalidate()
+            checkTimer = nil
+        }
+    }
+
+    @objc
+    public func reportNetworkSuccess() {
+        SwiftAssertIsOnMainThread(#function)
+
+        mayHaveOutage = true
+        hasOutage = false
+    }
+
+    @objc
+    public func reportNetworkFailure() {
+        SwiftAssertIsOnMainThread(#function)
+
+        mayHaveOutage = false
+    }
+}
diff --git a/SignalServiceKit/src/Network/WebSockets/TSSocketManager.m b/SignalServiceKit/src/Network/WebSockets/TSSocketManager.m
index 0c3d9b2f0..d8b928a5f 100644
--- a/SignalServiceKit/src/Network/WebSockets/TSSocketManager.m
+++ b/SignalServiceKit/src/Network/WebSockets/TSSocketManager.m
@@ -24,6 +24,7 @@
 #import "TextSecureKitEnv.h"
 #import "Threading.h"
 #import "WebSocketResources.pb.h"
+#import <SignalServiceKit/SignalServiceKit-Swift.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -677,6 +678,8 @@ NSString *const kNSNotification_SocketManagerStateDidChange = @"kNSNotification_
 
     // If socket opens, we know we're not de-registered.
     [TSAccountManager.sharedInstance setIsDeregistered:NO];
+
+    [OutageDetection.sharedManager reportNetworkSuccess];
 }
 
 - (void)webSocket:(SRWebSocket *)webSocket didFailWithError:(NSError *)error {
@@ -822,6 +825,8 @@ NSString *const kNSNotification_SocketManagerStateDidChange = @"kNSNotification_
         // Otherwise clean up and align state.
         [self applyDesiredSocketState];
     }
+
+    [OutageDetection.sharedManager reportNetworkFailure];
 }
 
 - (void)webSocket:(SRWebSocket *)webSocket
diff --git a/SignalMessaging/utils/WeakTimer.swift b/SignalServiceKit/src/Util/WeakTimer.swift
similarity index 96%
rename from SignalMessaging/utils/WeakTimer.swift
rename to SignalServiceKit/src/Util/WeakTimer.swift
index 073cdba86..f3553b6f4 100644
--- a/SignalMessaging/utils/WeakTimer.swift
+++ b/SignalServiceKit/src/Util/WeakTimer.swift
@@ -1,5 +1,5 @@
 //
-//  Copyright (c) 2017 Open Whisper Systems. All rights reserved.
+//  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
 //
 
 /**