Hi Folks,
after reinstalling one of our systems i started having the issue, incoming ftp-connections (and any other tcp/ip related connection) takes horrible long.
After looking around for a while on my system, i found this happens as soon as i provide a nameserver. Any incoming connection urges the server to do a reverse lookup, even for local adresses (192.168..).
I wonder if there is a way to tell the server to “never” do a reverse lookup or not to do a reverse lookup on local adresses (192.168.0.0/16 10.0.0.0/8 172.16.0.0/12). And i do not want to add all clients to the hostfile, nor do i want to miss a nameserver for connecting to the internet.
In my case it’s always been related to the fact that our primary corp network nameserver was temporarily down (and it had to time out before going to the backup nameserver). Even after the primary comes back online and has been online for days the QNX machine responds VERY slowly to all incoming ftp/telnet sessions.
I always end up rebooting and it fixes the issue right away.
So I wonder if it’s something to do with caching or if just restarting networking by hand would fix the issue.
A way to search incoming numbers is with reverselookupfree.net. This site proved to be very helpful when providing a phone number to reverse lookup the owner’s name and address. Most of the time you can do a reverse lookup free if you know how and have the tools.http://reverselookupfree.net
