Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

As far as I know SYN retransmissions: with rounding they occur 1, 3, 6, 12, 24, 48, and then 64 seconds apart. I want to do this on different interval time. what is the name of this parameter?

can I control on it in android and windows?

share|improve this question
up vote 2 down vote accepted


You can only control the first retransmission with HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\ID. After this, the retransmitted SYN packets are dynamically controlled (Source: KB 170359)


Per discussion in the comments, it appears that the KB article I referenced is flawed for Windows 7; it seems that changing SYN retransmission parameters is not supported.

share|improve this answer
is there any name for this parameter ? only for syn retransmission? is it the RTO? – Avihai Marchiano Jul 29 '12 at 12:41
It is called TCPInitialRtt, used for the first SYN retransmission. RTO is controlled indirectly with TcpMaxDataRetransmissions, but that isn't a timeout per-se... it's the number of attempts before Windows aborts the connection – Mike Pennington Jul 29 '12 at 12:42
I dont see this key. do i need to add it? dosnt it part of the TCP RFC? do you know how to do it in android? or a good search key words for this. Thank you!!!! – Avihai Marchiano Jul 29 '12 at 12:48
Windows 7 enterprise. – Avihai Marchiano Jul 29 '12 at 12:51
I haven't found android information, you might try Stack Overflow for that question. Add this to Win7 Enterprise if it isn't there. – Mike Pennington Jul 29 '12 at 12:54

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.