From: m@rtij.nl.invlalid   
      
   On Wed, 30 May 2012 20:49:58 +0000, Rick Jones wrote:   
      
   > Martijn Lievaart  wrote:   
   >> Retransmission should be after 0.3 seconds, not 3 seconds, so highly   
   >> unlikely.   
   >   
   > Which stack first retransmits SYNs at only 0.3 seconds?  Not that I'm a   
   > slavish adherent to IETF constants from the past, but I thought the   
   > chapter and verse called for an initial TCP retransmission timeout of 3   
   > seconds.  For example, on my Ubuntu 11.04 system running a 2.6.38 kernel   
   > I see:   
   >   
   > raj@tardy:~/netperf2_trunk/src$ tcpdump -i eth0 port 12865 tcpdump:   
   > verbose output suppressed, use -v or -vv for full protocol decode   
   > listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes   
   > 13:49:43.116918 IP tardy.56156 > testname.netperf: Flags [SEW], seq   
   > 1684409409, win 14600, options [mss 1460,sackOK,TS val 44556412 ecr   
   > 0,nop,wscale 7], length 0 13:49:46.123118 IP tardy.56156 >   
   > testname.netperf: Flags [SEW], seq 1684409409, win 14600, options [mss   
   > 1460,sackOK,TS val 44556713 ecr 0,nop,wscale 7], length 0   
   > 13:49:52.133103 IP tardy.56156 > testname.netperf: Flags [SEW], seq   
   > 1684409409, win 14600, options [mss 1460,sackOK,TS val 44557314 ecr   
   > 0,nop,wscale 7], length 0 13:50:04.153050 IP tardy.56156 >   
   > testname.netperf: Flags [SEW], seq 1684409409, win 14600, options [mss   
   > 1460,sackOK,TS val 44558516 ecr 0,nop,wscale 7], length 0   
      
   I was confused with normal retransmissons, my bad. Funny that my Ubuntu   
   12.04 with kernel 3.2.0-24 gives a different result:   
      
   Capturing on wlan0   
     0.000000   10.0.1.239 -> 1.2.3.4      TCP 74 41994 > telnet [SYN] Seq=0   
   Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=4167919 TSecr=0 WS=128   
     0.997676   10.0.1.239 -> 1.2.3.4      TCP 74 41994 > telnet [SYN] Seq=0   
   Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=4168169 TSecr=0 WS=128   
     3.001680   10.0.1.239 -> 1.2.3.4      TCP 74 41994 > telnet [SYN] Seq=0   
   Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=4168670 TSecr=0 WS=128   
     7.009669   10.0.1.239 -> 1.2.3.4      TCP 74 41994 > telnet [SYN] Seq=0   
   Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=4169672 TSecr=0 WS=128   
      
   But your original thought was correct, my bad.   
      
   M4   
      
   --- SoupGate-Win32 v1.05   
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