Index: src/OFSystemInfo.h
==================================================================
--- src/OFSystemInfo.h
+++ src/OFSystemInfo.h
@@ -44,10 +44,17 @@
  *
  * This maps to an @ref OFNumber.
  */
 extern OFNetworkInterfaceKey OFNetworkInterfaceIndex;
 
+/**
+ * @brief The IPv6 addresses of a network interface.
+ *
+ * This maps to an @ref OFData of @ref OFSocketAddress.
+ */
+extern OFNetworkInterfaceKey OFNetworkInterfaceIPv6Addresses;
+
 /**
  * @brief The IPv4 addresses of a network interface.
  *
  * This maps to an @ref OFData of @ref OFSocketAddress.
  */

Index: src/OFSystemInfo.m
==================================================================
--- src/OFSystemInfo.m
+++ src/OFSystemInfo.m
@@ -72,10 +72,13 @@
 #import "OFSystemInfo.h"
 #import "OFApplication.h"
 #import "OFArray.h"
 #import "OFData.h"
 #import "OFDictionary.h"
+#ifdef OF_HAVE_FILES
+ #import "OFFile.h"
+#endif
 #import "OFIRI.h"
 #import "OFLocale.h"
 #import "OFNumber.h"
 #import "OFOnce.h"
 #ifdef OF_HAVE_SOCKETS
@@ -82,10 +85,13 @@
 # import "OFSocket.h"
 # import "OFSocket+Private.h"
 #endif
 #import "OFString.h"
 
+#import "OFInvalidFormatException.h"
+#import "OFOpenItemFailedException.h"
+
 #if defined(OF_MACOS) || defined(OF_IOS)
 # ifdef HAVE_SYSDIR_H
 #  include <sysdir.h>
 # endif
 #endif
@@ -129,10 +135,12 @@
     NSSearchPathEnumerationState, char *);
 #endif
 
 #ifdef OF_HAVE_SOCKETS
 OFNetworkInterfaceKey OFNetworkInterfaceIndex = @"OFNetworkInterfaceIndex";
+OFNetworkInterfaceKey OFNetworkInterfaceIPv6Addresses =
+    @"OFNetworkInterfaceIPv6Addresses";
 OFNetworkInterfaceKey OFNetworkInterfaceIPv4Addresses =
     @"OFNetworkInterfaceIPv4Addresses";
 #endif
 
 #if defined(OF_AMD64) || defined(OF_X86)
@@ -884,10 +892,95 @@
 	return true;
 # else
 	return false;
 # endif
 }
+
+static bool
+queryNetworkInterfaceIPv6Addresses(OFMutableDictionary *ret)
+{
+# if defined(OF_LINUX) && defined(OF_HAVE_FILES)
+	OFFile *file;
+	OFString *line;
+	OFMutableDictionary *interface;
+	OFEnumerator *enumerator;
+
+	@try {
+		file = [OFFile fileWithPath: @"/proc/net/if_inet6" mode: @"r"];
+	} @catch (OFOpenItemFailedException *e) {
+		return false;
+	}
+
+	while ((line = [file readLine]) != nil) {
+		OFArray *components = [line
+		    componentsSeparatedByString: @" "
+					options: OFStringSkipEmptyComponents];
+		OFString *addressString, *name;
+		OFSocketAddress address;
+		OFMutableData *addresses;
+
+		if (components.count < 6)
+			continue;
+
+		addressString = [components objectAtIndex: 0];
+		name = [components objectAtIndex: 5];
+
+		if (addressString.length != 32)
+			continue;
+
+		interface = [ret objectForKey: name];
+		if (interface == nil) {
+			interface = [OFMutableDictionary dictionary];
+			[ret setObject: interface forKey: name];
+		}
+
+		memset(&address, 0, sizeof(address));
+		address.family = OFSocketAddressFamilyIPv6;
+
+		for (size_t i = 0; i < 32; i += 2) {
+			unsigned long long byte;
+
+			@try {
+				byte = [[addressString
+				    substringWithRange: OFMakeRange(i, 2)]
+				    unsignedLongLongValueWithBase: 16];
+			} @catch (OFInvalidFormatException *e) {
+				goto next_line;
+			}
+
+			if (byte > 0xFF)
+				goto next_line;
+
+			address.sockaddr.in6.sin6_addr.s6_addr[i / 2] =
+			    (unsigned char)byte;
+		}
+
+		addresses = [interface
+		    objectForKey: OFNetworkInterfaceIPv6Addresses];
+		if (addresses == nil) {
+			addresses = [OFMutableData
+			    dataWithItemSize: sizeof(OFSocketAddress)];
+			[interface setObject: addresses
+				      forKey: OFNetworkInterfaceIPv6Addresses];
+		}
+
+		[addresses addItem: &address];
+
+next_line:
+		continue;
+	}
+
+	enumerator = [ret objectEnumerator];
+	while ((interface = [enumerator nextObject]) != nil)
+		[[interface objectForKey: OFNetworkInterfaceIPv4Addresses]
+		    makeImmutable];
+
+	return false;
+# else
+	return false;
+# endif
+}
 
 static bool
 queryNetworkInterfaceIPv4Addresses(OFMutableDictionary *ret)
 {
 # if defined(HAVE_SYS_IOCTL_H) && defined(HAVE_NET_IF_H)
@@ -971,10 +1064,11 @@
 	bool success = false;
 	OFEnumerator *enumerator;
 	OFMutableDictionary *interface;
 
 	success |= queryNetworkInterfaceIndices(ret);
+	success |= queryNetworkInterfaceIPv6Addresses(ret);
 	success |= queryNetworkInterfaceIPv4Addresses(ret);
 
 	if (!success) {
 		objc_autoreleasePoolPop(pool);
 		return nil;

Index: tests/OFSystemInfoTests.m
==================================================================
--- tests/OFSystemInfoTests.m
+++ tests/OFSystemInfoTests.m
@@ -114,28 +114,40 @@
 #ifdef OF_HAVE_SOCKETS
 	networkInterfaces = [OFSystemInfo networkInterfaces];
 	[OFStdOut writeString: @"[OFSystemInfo] Network interfaces: "];
 	for (OFString *name in networkInterfaces) {
 		OFNetworkInterface interface;
-		OFData *IPv4Addresses;
+		OFData *IPv6Addresses, *IPv4Addresses;
 
 		if (!firstInterface)
 			[OFStdOut writeString: @"; "];
 
 		firstInterface = false;
 
 		[OFStdOut writeFormat: @"%@(", name];
 
 		interface = [networkInterfaces objectForKey: name];
+		IPv6Addresses = [interface
+		    objectForKey: OFNetworkInterfaceIPv6Addresses];
 		IPv4Addresses = [interface
 		    objectForKey: OFNetworkInterfaceIPv4Addresses];
+
+		for (size_t i = 0; i < IPv6Addresses.count; i++) {
+			const OFSocketAddress *address =
+			    [IPv6Addresses itemAtIndex: i];
+
+			if (i > 0)
+				[OFStdOut writeString: @", "];
+
+			[OFStdOut writeString: OFSocketAddressString(address)];
+		}
 
 		for (size_t i = 0; i < IPv4Addresses.count; i++) {
 			const OFSocketAddress *address =
 			    [IPv4Addresses itemAtIndex: i];
 
-			if (i > 0)
+			if (i > 0 || IPv6Addresses.count > 0)
 				[OFStdOut writeString: @", "];
 
 			[OFStdOut writeString: OFSocketAddressString(address)];
 		}