From: Stefan Rompf <stefan@loplof.de>
To: David Miller <davem@davemloft.net>
Subject: Re: sockets affected by IPsec always block (2.6.23)
Date: Wed, 5 Dec 2007 19:42:31 +0100
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Am Mittwoch, 5. Dezember 2007 08:12 schrieb David Miller:

> Actually, consider even a case like DNS.  Let's say the timeout
> is set to 2 seconds or something and you have 3 DNS servers
> listed, on different IPSEC destinations, in your resolv.conf
>
> Each IPSEC route that isn't currently resolved will cause packet loss
> of the DNS lookup request with xfrm_larval_drop set to '1'.
>
> If all 3 need to be resolved, the DNS lookup will fully fail
> which defeats the purpose of listing 3 servers for redundancy
> don't you think? :-)

In your example, the DNS server might actually stop responding to other 
clients while waiting for the (expected to be non-blocking) connect() to 
return. This is much much worse.

Stefan
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