Re: Sendto(2) Never Reaches Wire

From: Michael B Allen (mba2000_at_ioplex.com)
Date: 02/19/05 

Date: Sat, 19 Feb 2005 16:41:38 -0500

On Sat, 19 Feb 2005 11:41:31 -0500, Barry Margolin wrote:

>> [1] If I run tests back to back within a few seconds all requests are
>> sent successfully but if I wait a few minutes the first two packets
>> never reach the wire.
>
> My guess is the destination address isn't in the ARP cache when you send
> the first request. And that the OS will only buffer one packet while
> waiting for the ARP response, so if you send additional packets in quick
> succession they replace each other.

Yup. I bet that's exactly what's happening. Which means I probably *can*
do more than 2 or 3 async queries at the same time because once the ARP
cache is hot (has the DNS server / gateway's address) the success rate
should be much higher.

Thanks,
Mike

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