diff --git a/src/libstd/sys/common/net.rs b/src/libstd/sys/common/net.rs
index 274e495d70eb6..8b7af17f92b85 100644
--- a/src/libstd/sys/common/net.rs
+++ b/src/libstd/sys/common/net.rs
@@ -152,9 +152,19 @@ pub fn lookup_host(host: &str) -> io::Result<LookupHost> {
     init();
 
     let c_host = CString::new(host)?;
+    let hints = c::addrinfo {
+        ai_flags: 0,
+        ai_family: 0,
+        ai_socktype: c::SOCK_STREAM,
+        ai_protocol: 0,
+        ai_addrlen: 0,
+        ai_addr: ptr::null_mut(),
+        ai_canonname: ptr::null_mut(),
+        ai_next: ptr::null_mut()
+    };
     let mut res = ptr::null_mut();
     unsafe {
-        cvt_gai(c::getaddrinfo(c_host.as_ptr(), ptr::null(), ptr::null(),
+        cvt_gai(c::getaddrinfo(c_host.as_ptr(), ptr::null(), &hints,
                                &mut res))?;
         Ok(LookupHost { original: res, cur: res })
     }
@@ -591,3 +601,22 @@ impl fmt::Debug for UdpSocket {
             .finish()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use prelude::v1::*;
+
+    use super::*;
+    use collections::HashMap;
+
+    #[test]
+    fn no_lookup_host_duplicates() {
+        let mut addrs = HashMap::new();
+        let lh = match lookup_host("localhost") {
+            Ok(lh) => lh,
+            Err(e) => panic!("couldn't resolve `localhost': {}", e)
+        };
+        let _na = lh.map(|sa| *addrs.entry(sa).or_insert(0) += 1).count();
+        assert!(addrs.values().filter(|&&v| v > 1).count() == 0);
+    }
+}