I want to configure Haproxy for outgoing mail load balancing. my configuration file /etc/haproxy.cfg is. global maxconn 4096 # Total Max Connections. This is dependent on ulimit daemon nbproc 4 # Number of processing cores. Dual Dual-core Opteron is 4 cores for example. defaults mode tcp listen smtp_proxy 199.83.95.71:25 mode tcp option tcplog balance roundrobin # Load Balancing algorithm ## Define your servers to balance server r23.lbsmtp.org 74.117.x.x:25 weight 1 maxconn 512 check server r15.lbsmtp.org 199.71.x.x:25 weight 1 maxconn 512 check And when i start service haproxy i get this error. Starting HAproxy: [ALERT] 244/172148 (7354) : cannot bind socket for proxy smtp_proxy. Aborting. Please tell me where i am doing mistake.help will appreciated.