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sync-ack process not completing on windows 2012

1

Hi!

From windows 2012 I am trying to telnet to destination on specific port and its not working. I can do telnet from win 7 win 2008 from the same network. I did capture on win 2012 and looks like the win 2012 is not sending ACK.

19452   0.000270000 5.730763000 SRC Dst 64569   25000   TCP 64569 > 25000 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1  19452

29390   0.000100000 8.737071000 SRC Dst 64569   25000   TCP [TCP Retransmission] 64569 > 25000 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1 29390


29753   0.000484000 8.849849000 DST SRC 25000   64569   TCP 25000 > 64569 [ACK] Seq=1 Ack=1 Win=32775 Len=0 29753


48941   0.000538000 14.734428000    SRC DST 64569   25000   TCP [TCP Retransmission] 64569 > 25000 [SYN] Seq=0 Win=8192 Len=0 MSS=1460 SACK_PERM=1  48941


49454   0.000033000 14.847287000    DST SRC 25000   64569   TCP [TCP Dup ACK 29753#1] 25000 > 64569 [ACK] Seq=1 Ack=1 Win=32775 Len=0   49454

I have changed the IP address to SRC and DST

Src = windows 2012 from where i am doing telnet dst 25000

Anyone can help.

Thanks

asked 11 Apr ‘14, 07:53

capricorn800's gravatar image

capricorn800
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accept rate: 0%

edited 14 Apr ‘14, 03:00

grahamb's gravatar image

grahamb ♦
19.8k●3●30●206

One Answer:

2

You can try disabling ECN on windows 2012 by issuing

netsh interface tcp set global ecncapability=disabled

See http://serverfault.com/questions/526377/

answered 11 Apr '14, 10:51

mrEEde's gravatar image

mrEEde
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accept rate: 20%

Thanks the answer helped and fixed the problem.

(14 Apr '14, 02:04) capricorn800

@capricorn800

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(14 Apr '14, 03:00) grahamb ♦