Hi, My setup: Fedora Core 2 with 2.6.10-1.771_FC2smp kernel. I'm currently developing a simulator for load testing which needs to handle around 40-50K connections. A mixture of TCP and UDP. I changed the amount of file descriptors to 64000 with ulimit -n 64000 as root. But when I run and reach around 27000 TCP connections my application stops and dmesg writes the following: "out of socket memory" several times. I wonder what is the problem and how it can be fixed. Didn't have any luck at the mail archive or google. Any help appreciated. Br, /Andreas