On 07/19/2011 10:51 AM, Reza Lotun wrote: > would be resolved, bombarding amazon's dns servers with requests. After > diving in, I learned all Twisted connect* calls go through > socket.gethostbyname, which apparently does not do any DNS caching (much > to my surprise) unless something like nscd or a local caching nameserver > is running (we ended up using BIND).
socket.gethostbyname is just a wrapper around the libc implementation, and you're correct that it does no caching unless the NSS layer does, or the DNS query you're talking to does. > > Now, since we never ran a local caching nameserver before I wondered How did anything work then if you had no local DNS? > what changed. Could it have been that using the _newtls code (with > PyOpenSSL 0.12) removed some element of DNS caching that OpenSSL was > performing behind the scene? Is this possible? If so, then I just wanted A quick 10-line connectSSL script on my box running 10.1 does a DNS lookup per-connection. Are you sure this behaviour has changed? > to make sure everyone was aware that if you make a lot of DNS calls in a > Twisted server running this code, you too could experience problems if > you're not running a local caching nameserver. Well, TBH if you're not running a local caching nameserver, I am failing to see how anything works! _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
