diff --git a/liteeth/common.py b/liteeth/common.py
index 84ad436..3f80637 100644
--- a/liteeth/common.py
+++ b/liteeth/common.py
@@ -146,11 +146,14 @@ def _remove_from_layout(layout, *args):
     return r
 
 def convert_ip(s):
-    ip = 0
-    for e in s.split("."):
-        ip = ip << 8
-        ip += int(e)
-    return ip
+    if isinstance(s, str):
+        ip = 0
+        for e in s.split("."):
+            ip = ip << 8
+            ip += int(e)
+        return ip
+    else:
+        return s
 
 # Stream Layouts -----------------------------------------------------------------------------------
 
diff --git a/liteeth/core/__init__.py b/liteeth/core/__init__.py
index 7dcb8e2..26fc9f1 100644
--- a/liteeth/core/__init__.py
+++ b/liteeth/core/__init__.py
@@ -15,8 +15,7 @@ from liteeth.core.icmp import LiteEthICMP
 
 class LiteEthIPCore(Module, AutoCSR):
     def __init__(self, phy, mac_address, ip_address, clk_freq, with_icmp=True, dw=8):
-        if isinstance(ip_address, str):
-            ip_address = convert_ip(ip_address)
+        ip_address = convert_ip(ip_address)
         self.submodules.mac = LiteEthMAC(phy, dw, interface="crossbar", with_preamble_crc=True)
         self.submodules.arp = LiteEthARP(self.mac, mac_address, ip_address, clk_freq, dw=dw)
         self.submodules.ip  = LiteEthIP(self.mac, mac_address, ip_address, self.arp.table, dw=dw)
@@ -27,8 +26,7 @@ class LiteEthIPCore(Module, AutoCSR):
 
 class LiteEthUDPIPCore(LiteEthIPCore):
     def __init__(self, phy, mac_address, ip_address, clk_freq, with_icmp=True, dw=8):
-        if isinstance(ip_address, str):
-            ip_address = convert_ip(ip_address)
+        ip_address = convert_ip(ip_address)
         LiteEthIPCore.__init__(self, phy, mac_address, ip_address, clk_freq, dw=dw,
                                with_icmp=with_icmp)
         self.submodules.udp = LiteEthUDP(self.ip, ip_address, dw=dw)