Hi, I'm accessing a twisted-based XMLRPC server through an HTTP proxy which seems to leave outgoing connections open for a very long time (I think it waits for the server to close them on its own). This means that after a handful of remote method calls through this proxy, my server runs into file descriptor limits: Traceback (most recent call last): File "/usr/lib/python2.3/site-packages/twisted/python/log.py", line 65, in callWithLogger File "/usr/lib/python2.3/site-packages/twisted/python/log.py", line 52, in callWithContext File "/usr/lib/python2.3/site-packages/twisted/python/context.py", line 43, in callWithContext File "/usr/lib/python2.3/site-packages/twisted/internet/default.py", line 535, in _doReadOrWrite --- <exception caught here> --- File "/usr/lib/python2.3/site-packages/twisted/internet/tcp.py", line 625, in doRead File "/usr/src/build/475206-i386/install/usr/lib/python2.3/socket.py", line 167, in accept socket.error: (24, 'Too many open files') Which is easily checked by a netstat dump : $ netstat --inet --tcp -n -p | grep :8550 tcp 0 0 192.33.178.29:8550 193.49.124.107:30839 ESTABLISHED 3076/python tcp 0 0 192.33.178.29:8550 193.49.124.107:25463 ESTABLISHED 3076/python tcp 0 0 192.33.178.29:8550 193.49.124.107:37494 ESTABLISHED 3076/python tcp 0 0 192.33.178.29:8550 193.49.124.107:33910 ESTABLISHED 3076/python tcp 0 0 192.33.178.29:8550 193.49.124.107:20854 ESTABLISHED 3076/python ... ... and so on for exactly 998 lines Looking at the Twisted code, I see that very long timeouts have been defined for both protocols.http.HTTPFactory and web.server.Site (60*60*12, that is 12 hours!). If I override the "timeout" parameter when constructing the Site receiving XMLRPC connections, then the problem disappears: reactor.listenTCP(xmlrpc_port, server.Site(self, timeout=30), interface=xmlrpc_host) I think the default values in Twisted are quite bogus and should be changed to more sensible ones. 30 or 60 seconds is ok in the context of an HTTP connection. Very long timeouts on the other hand make the server very vulnerable. Regards Antoine.