diff --git a/DnsServerCore/Dns/DnsServer.cs b/DnsServerCore/Dns/DnsServer.cs
index 12547894..9add2814 100644
--- a/DnsServerCore/Dns/DnsServer.cs
+++ b/DnsServerCore/Dns/DnsServer.cs
@@ -413,14 +413,14 @@ namespace DnsServerCore.Dns
                         if (response.IsSigned)
                         {
                             //rfc8945 section 5.3
-                            response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, true, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, DnsResponseCode.NoError, response.Question, null, null, new DnsResourceRecord[] { response.Additional[response.Additional.Count - 1] }) { Tag = DnsServerResponseType.Authoritative };
+                            response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, true, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, DnsResponseCode.NoError, response.Question, null, null, new DnsResourceRecord[] { response.Additional[response.Additional.Count - 1] }, request.EDNS is null ? ushort.MinValue : _udpPayloadSize) { Tag = DnsServerResponseType.Authoritative };
                         }
                         else
                         {
                             if (response.Question[0].Type == DnsResourceRecordType.IXFR)
-                                response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, false, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, response.RCODE, response.Question, new DnsResourceRecord[] { response.Answer[0] }) { Tag = DnsServerResponseType.Authoritative }; //truncate response
+                                response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, false, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, response.RCODE, response.Question, new DnsResourceRecord[] { response.Answer[0] }, null, null, request.EDNS is null ? ushort.MinValue : _udpPayloadSize) { Tag = DnsServerResponseType.Authoritative }; //truncate response
                             else
-                                response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, true, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, response.RCODE, response.Question) { Tag = DnsServerResponseType.Authoritative };
+                                response = new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, true, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, response.RCODE, response.Question, null, null, null, request.EDNS is null ? ushort.MinValue : _udpPayloadSize) { Tag = DnsServerResponseType.Authoritative };
                         }
 
                         sendBufferStream.Position = 0;