Hi, As I understand you need to send a Busy response, if caller is the same as callee. There is no easy way to do it. You need to match your From and To headers' URIs and see if they are same or not. You can do it this way, but I dont guarantee that it works. And this way is quite ugly. You'd have to use exec_dst() function from exec.so module to execute some perl file (or PHP if you like it more). Inside this perl/PHP file match the URI from To: header field with URI from From: header field (read README file from exec module to see how you can get the header fields, it's not too difficult). Anyway, exec_dst() function will execute any system command and if that command prints out a SIP URI, it will append it as a Contact header field to your request (i hope im not wrong, because it was a long time since I havent used exec module). For instance, exec_dst("echo 'sip:127.0.0.1' "); should append a Contact header field as follows: Contact: sip:127.0.0.1 So, in your perl/PHP program match the header fields against each other. If they match (caller==callee), then print "sip:127.0.0.1" or smth like that. Then in your ser.cfg write like this if(!exec_dst("perl /path/to/perl/script/myscript.pl")) { #execute your perl/php code if(search("Contact:[ ]*sip:127\.0\.0\.1) ) { #see if Contact header was attached sl_send_reply("600", "Busy Everywhere"); break; }; }; ***I really hope that works, cause if it doesnt, you most probably have to quickly move to OpenSER (like you said in ur last email). <Error logs> I dont know what's causing this "ERROR: sl_reply_error used: I'm terribly sorry, server error occured (1/SL)". As for "ERROR: tcp_init: bind(6, 0x80bd7c0, 16)" error in your log, there's something already listening on this address and port. I think, you can avoid this error if you just add a listen directive somewhere before alias: listen=<your server ip> This should make SER listen on only this address and forget about the loopback address. <Cron jobs> More, you dont have to chmod 777 /tmp/ser_fifo in your cron. Just add this directive to your ser.cfg : fifo_mode = 666 Good luck, Andrey. On 8/30/06, ram &lt;talk2ram(a)gmail.com&gt; wrote: