diff --git a/repos/os/include/net/dhcp.h b/repos/os/include/net/dhcp.h
index 6429ebb2f8..7dcef7a6e6 100644
--- a/repos/os/include/net/dhcp.h
+++ b/repos/os/include/net/dhcp.h
@@ -199,7 +199,7 @@ class Net::Dhcp_packet
 		{
 			static constexpr Code CODE = Code::PARAM_REQ_LIST;
 
-			Parameter_request_list(Genode::size_t len) : Option(CODE, len) { }
+			Parameter_request_list(Genode::size_t len) : Option(CODE, (Genode::uint8_t)len) { }
 		};
 
 		/**
@@ -215,7 +215,7 @@ class Net::Dhcp_packet
 
 				static constexpr Code CODE = Code::DNS_SERVER;
 
-				Dns_server(Genode::size_t len) : Option(CODE, len) { }
+				Dns_server(Genode::size_t len) : Option(CODE, (Genode::uint8_t)len) { }
 
 				template <typename FUNC>
 				void for_each_address(FUNC && func) const
@@ -241,7 +241,7 @@ class Net::Dhcp_packet
 
 				static constexpr Code CODE = Code::DOMAIN_NAME;
 
-				Domain_name (Genode::size_t len) : Option(CODE, len) { }
+				Domain_name (Genode::size_t len) : Option(CODE, (Genode::uint8_t)len) { }
 
 				template <typename FUNC>
 				void with_string(FUNC && func) const
diff --git a/repos/os/include/net/ipv4.h b/repos/os/include/net/ipv4.h
index e819a074c2..f2f12dd752 100644
--- a/repos/os/include/net/ipv4.h
+++ b/repos/os/include/net/ipv4.h
@@ -187,7 +187,7 @@ class Net::Ipv4_packet
 		Ipv4_address         src()             const { return Ipv4_address((void *)&_src); }
 		Ipv4_address         dst()             const { return Ipv4_address((void *)&_dst); }
 
-		void header_length(Genode::size_t v)     { Offset_0_u8::Ihl::set(_offset_0_u8, v); }
+		void header_length(Genode::size_t v)     { Offset_0_u8::Ihl::set(_offset_0_u8, (Offset_0_u8::access_t)v); }
 		void version(Genode::uint8_t v)          { Offset_0_u8::Version::set(_offset_0_u8, v); }
 		void diff_service(Genode::uint8_t v)     { Offset_1_u8::Dscp::set(_offset_1_u8, v); }
 		void ecn(Genode::uint8_t v)              { Offset_1_u8::Ecn::set(_offset_1_u8, v); }
@@ -209,7 +209,7 @@ class Net::Ipv4_packet
 		void fragment_offset(Genode::size_t v)
 		{
 			Genode::uint16_t be = host_to_big_endian(_offset_6_u16);
-			Offset_6_u16::Fragment_offset::set(be, v);
+			Offset_6_u16::Fragment_offset::set(be, (Offset_6_u16::access_t)v);
 			_offset_6_u16 = host_to_big_endian(be);
 		}
 
diff --git a/repos/os/include/net/port.h b/repos/os/include/net/port.h
index 33ff853ad1..91b5ad17c9 100644
--- a/repos/os/include/net/port.h
+++ b/repos/os/include/net/port.h
@@ -50,7 +50,7 @@ Genode::size_t Net::ascii_to(const char *s, Net::Port &result)
 {
 	using namespace Genode;
 
-	unsigned value = 0;
+	uint16_t value = 0;
 	size_t const consumed = ascii_to_unsigned(s, value, 0);
 	result = Net::Port(value);
 	return consumed;