diff --git a/defaults.go b/defaults.go
index 2b36742f..39326a0f 100644
--- a/defaults.go
+++ b/defaults.go
@@ -48,7 +48,7 @@ func (dns *Msg) SetIxfr(z string, serial uint32) {
 	dns.Question = make([]Question, 1)
 	dns.Ns = make([]RR, 1)
 	s := new(RR_SOA)
-	s.Hdr = RR_Header{z, TypeSOA, ClassINET, DefaultTtl, 0}
+	s.Hdr = RR_Header{z, TypeSOA, ClassINET, DefaultTTL, 0}
 	s.Serial = serial
 
 	dns.Question[0] = Question{z, TypeIXFR, ClassINET}
diff --git a/dns.go b/dns.go
index c09d3ee6..04f83abc 100644
--- a/dns.go
+++ b/dns.go
@@ -52,7 +52,7 @@ const (
 	Year68         = 2 << (32 - 1) // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
 	DefaultMsgSize = 4096          // A standard default for larger than 512 packets.
 	MaxMsgSize     = 65536         // Largest possible DNS packet.
-	DefaultTtl     = 3600          // Default Ttl.
+	DefaultTTL     = 3600          // Default Ttl.
 )
 
 // Error represents a DNS error