diff --git a/src/proto.rs b/src/proto.rs
index f0c8f9b..4f7e24d 100644
--- a/src/proto.rs
+++ b/src/proto.rs
@@ -186,15 +186,16 @@ impl DNSHeader {
 
         let message_type = DNSMessageType::from(datagram[2] & Self::QR_MASK != 0);
         let opcode = DNSOpCode::try_from((datagram[2] & Self::OPCODE_MASK) >> Self::OPCODE_OFFSET)?;
+
         let authorative_answer = (datagram[2] & Self::AA_MASK) != 0;
         let truncated = (datagram[2] & Self::TC_MASK) != 0;
         let recursion_desired = (datagram[2] & Self::RD_MASK) != 0;
+        let recursion_available = (datagram[3] & Self::RA_MASK) != 0;
 
-        let recursion_available = (datagram[2] & Self::RA_MASK) != 0;
         let authentic_data = (datagram[2] & Self::AD_MASK) != 0;
         let checking_disabled = (datagram[2] & Self::CD_MASK) != 0;
-        let response_code = DNSRCode::try_from(datagram[3] & Self::RCODE_MASK)?;
 
+        let response_code = DNSRCode::try_from(datagram[3] & Self::RCODE_MASK)?;
         let query_count = u16::from_be_bytes((datagram[4..6]).try_into().unwrap());
         let answer_count = u16::from_be_bytes((datagram[6..8]).try_into().unwrap());
         let name_server_count = u16::from_be_bytes((datagram[8..10]).try_into().unwrap());
@@ -512,5 +513,101 @@ mod tests {
                 Ok(())
             }
         }
+
+        mod authorative_answer {
+            use super::super::super::*;
+
+            #[test]
+            fn yes() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.authorative_answer, true);
+                Ok(())
+            }
+
+            #[test]
+            fn no() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.authorative_answer, false);
+                Ok(())
+            }
+        }
+
+        mod truncated {
+            use super::super::super::*;
+
+            #[test]
+            fn yes() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.truncated, true);
+                Ok(())
+            }
+
+            #[test]
+            fn no() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.truncated, false);
+                Ok(())
+            }
+        }
+
+        mod recursion_desired {
+            use super::super::super::*;
+
+            #[test]
+            fn yes() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.recursion_desired, true);
+                Ok(())
+            }
+
+            #[test]
+            fn no() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.recursion_desired, false);
+                Ok(())
+            }
+        }
+
+        mod recursion_available {
+            use super::super::super::*;
+
+            #[test]
+            fn yes() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.recursion_available, true);
+                Ok(())
+            }
+
+            #[test]
+            fn no() -> Result<(), DNSParseError> {
+                let dns_query = [
+                    0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                ];
+                let parse_result = DNSHeader::from_udp_datagram(&dns_query);
+                assert_eq!(parse_result?.recursion_available, false);
+                Ok(())
+            }
+        }
     }
 }