diff --git a/src/iface/interface/mod.rs b/src/iface/interface/mod.rs
index 7eed974e..47b2ae00 100644
--- a/src/iface/interface/mod.rs
+++ b/src/iface/interface/mod.rs
@@ -898,7 +898,6 @@ impl InterfaceInner {
     fn lookup_hardware_addr<Tx>(
         &mut self,
         tx_token: Tx,
-        src_addr: &IpAddress,
         dst_addr: &IpAddress,
         fragmenter: &mut Fragmenter,
     ) -> Result<(HardwareAddress, Tx), DispatchError>
@@ -966,11 +965,9 @@ impl InterfaceInner {
             _ => (), // XXX
         }
 
-        match (src_addr, dst_addr) {
+        match dst_addr {
             #[cfg(all(feature = "medium-ethernet", feature = "proto-ipv4"))]
-            (&IpAddress::Ipv4(src_addr), IpAddress::Ipv4(dst_addr))
-                if matches!(self.caps.medium, Medium::Ethernet) =>
-            {
+            IpAddress::Ipv4(dst_addr) if matches!(self.caps.medium, Medium::Ethernet) => {
                 net_debug!(
                     "address {} not in neighbor cache, sending ARP request",
                     dst_addr
@@ -980,7 +977,9 @@ impl InterfaceInner {
                 let arp_repr = ArpRepr::EthernetIpv4 {
                     operation: ArpOperation::Request,
                     source_hardware_addr: src_hardware_addr,
-                    source_protocol_addr: src_addr,
+                    source_protocol_addr: self
+                        .get_source_address_ipv4(&dst_addr)
+                        .ok_or(DispatchError::NoRoute)?,
                     target_hardware_addr: EthernetAddress::BROADCAST,
                     target_protocol_addr: dst_addr,
                 };
@@ -999,7 +998,7 @@ impl InterfaceInner {
             }
 
             #[cfg(feature = "proto-ipv6")]
-            (&IpAddress::Ipv6(src_addr), IpAddress::Ipv6(dst_addr)) => {
+            IpAddress::Ipv6(dst_addr) => {
                 net_debug!(
                     "address {} not in neighbor cache, sending Neighbor Solicitation",
                     dst_addr
@@ -1012,7 +1011,7 @@ impl InterfaceInner {
 
                 let packet = Packet::new_ipv6(
                     Ipv6Repr {
-                        src_addr,
+                        src_addr: self.get_source_address_ipv6(&dst_addr),
                         dst_addr: dst_addr.solicited_node(),
                         next_header: IpProtocol::Icmpv6,
                         payload_len: solicit.buffer_len(),
@@ -1059,12 +1058,8 @@ impl InterfaceInner {
 
         #[cfg(feature = "medium-ieee802154")]
         if matches!(self.caps.medium, Medium::Ieee802154) {
-            let (addr, tx_token) = self.lookup_hardware_addr(
-                tx_token,
-                &ip_repr.src_addr(),
-                &ip_repr.dst_addr(),
-                frag,
-            )?;
+            let (addr, tx_token) =
+                self.lookup_hardware_addr(tx_token, &ip_repr.dst_addr(), frag)?;
             let addr = addr.ieee802154_or_panic();
 
             self.dispatch_ieee802154(addr, tx_token, meta, packet, frag);
@@ -1091,12 +1086,7 @@ impl InterfaceInner {
         #[cfg(feature = "medium-ethernet")]
         let (dst_hardware_addr, mut tx_token) = match self.caps.medium {
             Medium::Ethernet => {
-                match self.lookup_hardware_addr(
-                    tx_token,
-                    &ip_repr.src_addr(),
-                    &ip_repr.dst_addr(),
-                    frag,
-                )? {
+                match self.lookup_hardware_addr(tx_token, &ip_repr.dst_addr(), frag)? {
                     (HardwareAddress::Ethernet(addr), tx_token) => (addr, tx_token),
                     (_, _) => unreachable!(),
                 }
diff --git a/src/iface/interface/tests/ipv4.rs b/src/iface/interface/tests/ipv4.rs
index 1c394f2a..c2c8ce46 100644
--- a/src/iface/interface/tests/ipv4.rs
+++ b/src/iface/interface/tests/ipv4.rs
@@ -456,7 +456,6 @@ fn test_handle_valid_arp_request(#[case] medium: Medium) {
     assert_eq!(
         iface.inner.lookup_hardware_addr(
             MockTxToken,
-            &IpAddress::Ipv4(local_ip_addr),
             &IpAddress::Ipv4(remote_ip_addr),
             &mut iface.fragmenter,
         ),
@@ -505,7 +504,6 @@ fn test_handle_other_arp_request(#[case] medium: Medium) {
     assert_eq!(
         iface.inner.lookup_hardware_addr(
             MockTxToken,
-            &IpAddress::Ipv4(Ipv4Address([0x7f, 0x00, 0x00, 0x01])),
             &IpAddress::Ipv4(remote_ip_addr),
             &mut iface.fragmenter,
         ),
@@ -564,7 +562,6 @@ fn test_arp_flush_after_update_ip(#[case] medium: Medium) {
     assert_eq!(
         iface.inner.lookup_hardware_addr(
             MockTxToken,
-            &IpAddress::Ipv4(local_ip_addr),
             &IpAddress::Ipv4(remote_ip_addr),
             &mut iface.fragmenter,
         ),
diff --git a/src/iface/interface/tests/ipv6.rs b/src/iface/interface/tests/ipv6.rs
index 785daba1..f6e214e7 100644
--- a/src/iface/interface/tests/ipv6.rs
+++ b/src/iface/interface/tests/ipv6.rs
@@ -834,7 +834,6 @@ fn test_handle_valid_ndisc_request(#[case] medium: Medium) {
     assert_eq!(
         iface.inner.lookup_hardware_addr(
             MockTxToken,
-            &IpAddress::Ipv6(local_ip_addr),
             &IpAddress::Ipv6(remote_ip_addr),
             &mut iface.fragmenter,
         ),