Too many open files

[Simon Waters]

"Garrido, Alberto" wrote:
> 
> Our Firewall was denying all TCP connections from/to DNS's servers.
> I can't see the relation between this, and "Too many open files" error.
> That was the problem.

UNIX uses the concept of file to represent many things. For
example a disk drive is presented as a file in /dev, a terminal
is presented as a file (Try "echo Hello World >/dev/ttyxxxx",
make sure you get the right device file corresponding to your
terminal.

So it shouldn't be surprising that a network connection (or
socket) is treated as a file.

I assume it is trying to create connections to a number of DNS
servers for which it is a secondary, and failing. Or perhaps a
request for data larger than can be handled in UDP is repeated,
each time using another socket. Anyway TCP is required for
standard conforming implementations of DNS.