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Re: [Condor-users] windows 7 silently drops udp when no arp entry is present

Forgot to mention: we had a similar (the same?) problem with WinXP a few years back:


Adding D_NETWORK logging solved it then, but doesn't now. Maybe the implementation has changed, or the added delay simply isn't enough?


Rob de Graaf
Erasmus MC

On 07/26/2012 07:59 PM, Rob de Graaf wrote:
Hello list,

We're having a problem with Windows 7 nodes. I believe this is it:


It seems the condor_master on the client tries to send an update to the
collector. This update consists of two fragments, but only the last
fragment is actually sent. The first fragment is dropped because there
isn't an arp entry for the collector yet. Subsequent updates are fully
sent, until the arp cache entry for the collector times out. At least,
that is what I think is going on. :)

I have left a ping -t running from a cmd window to prevent the arp cache
entry from going stale, and all updates since have gone through
completely. I can't raise the arp cache timeout, so I am thinking of
lowering master_update_interval to act as a ping, but Windows 7 has a
very short timeout between 15 and 45 seconds:


Less than 15 seconds seems a very short update interval. We have about
10,000 nodes in the pool. With TCP updates, we'd need a very large
number of sockets and file descriptors on the collector. I don't even
know if that would work. The manual used to recommend against it but
seems less insistent now. Have TCP updates been improved upon lately?


Rob de Graaf
Erasmus MC
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