We have a number of Firebird servers that run on both Windows and Fedora
Linux boxes. One of the major differences between these server environments
that we have noticed is the security level on Linux in regards to TCP/IP
client connections on its ports.

A recent update to Linux that our servers got increased the resillience to
client TCP port connections, by forcing the connection to be dropped after a
certain amount of inactivity (it appears to be about 10 minutes from our
experience). I've tried to find out from various Linux forums if this is
something that can be controlled at the server level by port number, but
haven't had much luck in determining what exactly is policing this.

In the case of Firebird, its causing any software that is a 'client' to the
Firebird server (such as any Delphi applications we write, or IBExpert or
other 3rd party admin tools) to lock up when the 10 minutes of inactivity
has occurred. I was thinking that we can't be the only folks being affected
by this, and although some people in the Linux community have told us that
we should send some form of 'Keep Alive' message from the client to the
server to stop this, it would appear that this is a bandaid to what could be
simply a setting in Linux security to stop this.

Our experience with products like IBExpert is that when the Linux server
decides to close the port due to inactivity, the software (at least the
version we have) is not handling this very well at all, crashing, causing
exceptions, etc. This may have been addressed with a later update than what
we have but the problem is not limited to that product at all. Its going to
affect any client software we develop that works with Firebird, where the
user sits idle for 10 minutes and then attempts another query, etc.

What strategies have others used to get around this issue? Is there
something simple that I need to set that I'm overlooking?

Thanks in advance for any suggestions or advice.

Myles

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Myles Wakeham
Director of Engineering
Tech Solutions USA, Inc.
Scottsdale, Arizona USA
www.techsolusa.com
Phone +1-480-451-7440