diff --git a/Project.toml b/Project.toml
index c2da874..7ad865a 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "NetworkProtocols"
 uuid = "cc8e9863-198f-4c11-8208-8a22403099d5"
 authors = ["Christian Rorvik <christian.rorvik@gmail.com>"]
-version = "0.2.5"
+version = "0.2.6"
 
 [deps]
 FunctionWrappers = "069b7b12-0de2-55c6-9aab-29f3d0a68a2e"
diff --git a/src/ip.jl b/src/ip.jl
index 0dfcda6..c9d23e9 100644
--- a/src/ip.jl
+++ b/src/ip.jl
@@ -55,3 +55,7 @@ function decode_ipv4(data::DenseVector{UInt8})
             p + h.header_length,
             (Int(h.total_length - h.header_length),)))
 end
+
+function ismulticast(ip::IPv4)
+    ip"224.0.0.0" <= ip <= ip"239.255.255.255"
+end
diff --git a/test/ip_tests.jl b/test/ip_tests.jl
index 0266881..bbeca7b 100644
--- a/test/ip_tests.jl
+++ b/test/ip_tests.jl
@@ -16,4 +16,9 @@
     @test length(ipp.payload) == 48
 end
 
+@testset "ismulticast" begin
+    @test all(ismulticast(addr) for addr in multicast_addresses)
+    @test all(!ismulticast(addr) for addr in non_multicast_addresses)
+end
+
 end
diff --git a/test/test_data.jl b/test/test_data.jl
index d4086b5..b387fa9 100644
--- a/test/test_data.jl
+++ b/test/test_data.jl
@@ -7,3 +7,16 @@ const dns_packet = [
     0x02, 0x63, 0x73, 0x05, 0x6d, 0x69, 0x61, 0x6d, 0x69, 0x03, 0x65, 0x64, 0x75, 0x00, 0x00, 0x01,
     0x00, 0x01
 ]
+
+const multicast_addresses = [
+    ip"224.0.0.0",
+    ip"224.0.0.10",
+    ip"224.0.10.20",
+    ip"239.255.255.255"
+]
+
+const non_multicast_addresses = [
+    ip"127.0.0.1",
+    ip"10.0.0.10",
+    ip"192.168.0.1"
+]