I've noticed that when using the NTS v1.40 PPPoE client, two DNS requests are transmitted for every one issued by the user.
Note: Frame 9, 10 below
The of course results in the DNS server having to send two responses...see Frames 11,12.
This behavior does NOT occur when the same exact PC issues DNS request over a bridged ADSL connection. In Frames 24-27, the PPPoE connection is torn down. In frames 30-31 you now see just a single DNS request and response.
The DNS requests were generated simply by pinging host sites that were known NOT to be already in the local DNS cache.
This behavior only occurs from Windows NT (SP5) systems. Only a single DNS request is generated on Windows 95 and Windows 2000 systems.
\"Flags \",\"Frame \",\"Delta Time \",\"Destination \",\"Source \",\"Bytes\",\"Protocol \",\"Summary\" " M "," 1","0.000.000 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Echo Request" " "," 2","0.010.551 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Echo Reply" " "," 3","7.051.981 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Echo Request" " "," 4","0.010.381 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Echo Reply" " "," 5","6.865.145 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Echo Request" " "," 6","0.010.246 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Echo Reply" " "," 7","6.864.175 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Echo Request" " "," 8","0.009.961 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Echo Reply" " "," 9","0.396.809 ","[205.152.0.20] ","[209.214.101.138] "," 82 ","DNS"," C ID=1 OP=QUERY NAME=www.novell.com" " "," 10","0.000.125 ","[205.152.0.20] ","[209.214.101.138] "," 82 ","DNS"," C ID=1 OP=QUERY NAME=www.novell.com" " "," 11","0.225.464 ","[209.214.101.138] ","[205.152.0.20] "," 291 ","DNS"," R ID=1 STAT=OK NAME=www.novell.com" " "," 12","0.005.663 ","[209.214.101.138] ","[205.152.0.20] "," 291 ","DNS"," R ID=1 STAT=OK NAME=www.novell.com" " "," 13","0.004.927 ","[205.152.0.20] ","[209.214.101.138] "," 78 ","ICMP"," Destination unreachable (Port unreachable)" " "," 14","0.013.579 ","www.novell.com ","[209.214.101.138] "," 82 ","ICMP"," Echo" " "," 15","0.033.990 ","[209.214.101.138] ","www.novell.com "," 82 ","ICMP"," Echo reply" " "," 16","0.950.579 ","www.novell.com ","[209.214.101.138] "," 82 ","ICMP"," Echo" " "," 17","0.034.162 ","[209.214.101.138] ","www.novell.com "," 82 ","ICMP"," Echo reply" " "," 18","0.981.699 ","www.novell.com ","[209.214.101.138] "," 82 ","ICMP"," Echo" " "," 19","0.033.610 ","[209.214.101.138] ","www.novell.com "," 82 ","ICMP"," Echo reply" " "," 20","0.966.272 ","www.novell.com ","[209.214.101.138] "," 82 ","ICMP"," Echo" " "," 21","0.033.299 ","[209.214.101.138] ","www.novell.com "," 82 ","ICMP"," Echo reply" " "," 22","3.185.166 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Echo Request" " "," 23","0.010.254 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Echo Reply" " "," 24","3.114.411 ","001067008D8A ","Intel 22B210 "," 60 ","PPP"," LCP Terminate Request" " "," 25","0.000.102 ","001067008D8A ","Intel 22B210 "," 60 ","PPPoE"," : Discovery Stage " " "," 26","0.019.183 ","Intel 22B210 ","001067008D8A "," 60 ","PPP"," LCP Terminate Ack" " "," 27","0.002.823 ","[224.0.0.2] ","[209.214.101.138] "," 60 ","IGMP"," Type 7, Leave Group" " "," 28","16.307.300 ","Broadcast ","Intel 22B210 "," 60 ","ARP"," C PA=[205.152.56.129] PRO=IP" " "," 29","0.011.280 ","Intel 22B210 ","Cisco1EC60B0 "," 60 ","ARP"," R PA=[205.152.56.129] HA=Cisco1EC60B0 PRO=IP" " "," 30","0.000.423 ","[205.152.0.20] ","[205.152.56.157] "," 73 ","DNS"," C ID=1 OP=QUERY NAME=www.yahoo.com" " "," 31","0.017.884 ","[205.152.56.157] ","[205.152.0.20] "," 467 ","DNS"," R ID=1 STAT=OK NAME=www.yahoo.com" " "," 32","0.010.539 ","www.yahoo.akadns. ","[205.152.56.157] "," 74 ","ICMP"," Echo" " "," 33","0.092.415 ","[205.152.56.157] ","www.yahoo.akadns. "," 74 ","ICMP"," Echo reply" " "," 34","0.897.543 ","www.yahoo.akadns. ","[205.152.56.157] "," 74 ","ICMP"," Echo" " "," 35","0.091.930 ","[205.152.56.157] ","www.yahoo.akadns. "," 74 ","ICMP"," Echo reply" " "," 36","0.923.755 ","www.yahoo.akadns. ","[205.152.56.157] "," 74 ","ICMP"," Echo" " "," 37","0.092.282 ","[205.152.56.157] ","www.yahoo.akadns. "," 74 ","ICMP"," Echo reply" " "," 38","0.939.482 ","www.yahoo.akadns. ","[205.152.56.157] "," 74 ","ICMP"," Echo" " "," 39","0.091.867 ","[205.152.56.157] ","www.yahoo.akadns. "," 74 ","ICMP"," Echo reply"