How to configure kamailio server with load balancing and asterisk? [closed]

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Closed 4 years ago.

I want to configure Kamailio server so that traffic will be forwarded to other four asterisk servers equally. It is working fine with a single asterisk box but I am unable to forward a call to another asterisk box.

Here is the kamailio.cfg that I am using.

#!KAMAILIO
 
#!define WITH_MYSQL
#!define WITH_AUTH
#!define WITH_USRLOCDB
#!define WITH_NAT
#!define WITH_ASTERISK
 
 
# *** Value defines - IDs used later in config
#!ifdef WITH_MYSQL
# - database URL - used to connect to database server by modules such
#       as: auth_db, acc, usrloc, a.s.o.
#!define DBURL "mysql://root:PASS@127.0.0.1/openser"
#!ifdef WITH_ASTERISK
#!define DBASTURL "mysql://root:PASS@127.0.0.1/db_portal_mahtab"
#!endif
#!endif
#!ifdef WITH_MULTIDOMAIN
# - the value for 'use_domain' parameters
#!define MULTIDOMAIN 1
#!else
#!define MULTIDOMAIN 0
#!endif
 
# - flags
#   FLT_ - per transaction (message) flags
#	FLB_ - per branch flags
#!define FLT_ACC 1
#!define FLT_ACCMISSED 2
#!define FLT_ACCFAILED 3
#!define FLT_NATS 5
 
#!define FLB_NATB 6
#!define FLB_NATSIPPING 7
 
####### Global Parameters #########
 
#!ifdef WITH_DEBUG
debug=4
log_stderror=yes
#!else
debug=4
log_stderror=no
#!endif

log_name="kamailio"

memdbg=5
memlog=5
 log_facility=LOG_LOCAL0
 fork=yes
children=4
 
#disable_tcp=yes
local aliases
   based on reverse DNS on IPs (default on) */
#auto_aliases=no
#alias="localhost"
listen=udp:IPADDRESS:5060
 
;port=5060
 
#!ifdef WITH_TLS
enable_tls=yes
#!endif
 
tcp_connection_lifetime=3605
 
#!ifdef WITH_VOICEMAIL
# VoiceMail Routing on offline, busy or no answer
#
# - by default Voicemail server IP is empty to avoid misrouting
voicemail.srv_ip = "" desc "VoiceMail IP Address"
voicemail.srv_port = "5060" desc "VoiceMail Port"
#!endif
  
#!ifdef WITH_ASTERISK
asterisk.bindip = "IPADDRESSA" desc "Asterisk IP Address"
asterisk.bindport = "5080" desc "Asterisk Port"
kamailio.bindip = "IPADDRESSB" desc "Kamailio IP Address"
kamailio.bindport = "5060" desc "Kamailio Port"
#!endif
 
####### Modules Section ########
 
# set paths to location of modules (to sources or installation folders)
#!ifdef WITH_SRCPATH
mpath="modules_k:modules"
#!else
mpath="/usr/local/lib/kamailio/modules_k/:/usr/local/lib/kamailio/modules/:/usr/local/lib/kamailio/modules_s/"
#!endif
 
#!ifdef WITH_MYSQL
loadmodule "db_mysql.so"
#!endif
loadmodule "mi_datagram.so"
loadmodule "dispatcher.so"
loadmodule "mi_fifo.so"
loadmodule "kex.so"
loadmodule "tm.so"
loadmodule "tmx.so"
loadmodule "sl.so"
loadmodule "rr.so"
loadmodule "pv.so"
loadmodule "maxfwd.so"
loadmodule "usrloc.so"
loadmodule "registrar.so"
loadmodule "textops.so"
loadmodule "siputils.so"
loadmodule "xlog.so"
loadmodule "sanity.so"
loadmodule "ctl.so"
loadmodule "cfg_rpc.so"
loadmodule "mi_rpc.so"
loadmodule "acc.so"
loadmodule "rtimer.so"
loadmodule "sqlops.so"
loadmodule "htable.so"
loadmodule "ipops.so"

route[CDRS] {
	sql_query("ca","call kamailio_cdrs()","rb");
	sql_query("ca","call kamailio_rating('default')","rb");
 
}


modparam("rtimer", "timer", "name=tst;interval=300;mode=1;")
modparam("rtimer", "exec", "timer=tst;route=STATS")
modparam("rtimer", "timer", "name=cdr;interval=300;mode=1;")
modparam("rtimer", "exec", "timer=cdr;route=CDRS")
 
modparam("sqlops","sqlcon","ca=>mysql://root:PASS@127.0.0.1/openser")

 
modparam("htable", "htable", "stats=>size=6;")
 route[STATS] {
 
	# clean very old records
	$var(tmc) = $var(tmc) + 1;
	$var(x) = $var(tmc) mod 144;
	if($var(x) == 0)
	    sql_query("ca",
			"delete from statistics where time_stamp<$Ts - 864000",
			"ra");
 
	# insert values for Kamailio internal statistics
	sql_query("ca",
		"insert into statistics (time_stamp,shm_used_size,"
		"shm_real_used_size,shm_max_used_size,shm_free_used_size,"
		"ul_users,ul_contacts) values ($Ts,$stat(used_size),"
		"$stat(real_used_size),$stat(max_used_size),$stat(free_size),"
		"$stat(location-users),$stat(location-contacts))",
		"ra");
 
	# init the values for first execution, compute the diff for the rest
	if($var(tmc)==1)
	{
		$var(rcv_req_diff) = $stat(rcv_requests);
		$var(fwd_req_diff) = $stat(fwd_requests);
		$var(2xx_trans_diff) = $stat(2xx_transactions);
	} else {
		$var(rcv_req_diff) = $stat(rcv_requests) - $sht(stats=>last_rcv_req);
		$var(fwd_req_diff) = $stat(fwd_requests) - $sht(stats=>last_fwd_req);
		$var(2xx_trans_diff) = $stat(2xx_transactions) 
									- $sht(stats=>last_2xx_trans);
	}
	# update the values for stats stored in cache (htable)
	$sht(stats=>last_rcv_req) = $stat(rcv_requests);
	$sht(stats=>last_fwd_req) = $stat(fwd_requests);
	$sht(stats=>last_2xx_trans) = $stat(2xx_transactions);
 
	# insert values for stats computed in config
	sql_query("ca",
		"update statistics set tm_active=$stat(inuse_transactions),"
		"rcv_req_diff=$var(rcv_req_diff),fwd_req_diff=$var(fwd_req_diff),"
		"2xx_trans_diff=$var(2xx_trans_diff) where time_stamp=$Ts",
		"ra");
}

#!ifdef WITH_AUTH
loadmodule "auth.so"
loadmodule "auth_db.so"
#!ifdef WITH_IPAUTH
loadmodule "permissions.so"
#!endif
#!endif
 
#!ifdef WITH_ALIASDB
loadmodule "alias_db.so"
#!endif
 
#!ifdef WITH_SPEEDDIAL
loadmodule "speeddial.so"
#!endif
 
#!ifdef WITH_MULTIDOMAIN
loadmodule "domain.so"
#!endif
 
#!ifdef WITH_PRESENCE
loadmodule "presence.so"
loadmodule "presence_xml.so"
#!endif
 
#!ifdef WITH_NAT
loadmodule "nathelper.so"
loadmodule "rtpproxy.so"
#!endif
 
#!ifdef WITH_TLS
loadmodule "tls.so"
#!endif
 
#!ifdef WITH_ANTIFLOOD
loadmodule "htable.so"
loadmodule "pike.so"
#!endif
 
#!ifdef WITH_XMLRPC
loadmodule "xmlrpc.so"
#!endif
 
#!ifdef WITH_DEBUG
loadmodule "debugger.so"
#!endif
 
#!ifdef WITH_ASTERISK
loadmodule "uac.so"
#!endif
 



# ----------------- setting module-specific parameters ---------------
 
 
# ----- mi_fifo params -----
modparam("mi_fifo", "fifo_name", "/tmp/kamailio_fifo")
 
 
# ----- tm params -----
# auto-discard branches from previous serial forking leg
modparam("tm", "failure_reply_mode", 3)
# default retransmission timeout: 30sec
modparam("tm", "fr_timer", 30000)
# default invite retransmission timeout after 1xx: 120sec
modparam("tm", "fr_inv_timer", 120000)
 
modparam("dispatcher", "db_url","mysql://root:PASS@127.0.0.1/openser")
modparam("dispatcher", "table_name", "dispatcher")
#modparam("dispatcher", "ds_ping_interval", 3)
modparam("dispatcher", "ds_ping_from", "sip:dispatcher@localhost")
modparam("dispatcher", "force_dst", 1)
modparam("dispatcher", "ds_ping_method", "INFO")
modparam("dispatcher", "ds_ping_reply_codes", "class=2;code=403;code=404;code=484;code=488;code=481;class=3;class=408 ")
# do failover
modparam("dispatcher", "flags", 2)
modparam("dispatcher", "dst_avp", "$avp(AVP_DST)")
modparam("dispatcher", "grp_avp", "$avp(AVP_GRP)")
modparam("dispatcher", "cnt_avp", "$avp(AVP_CNT)")
# -----cmd
modparam("mi_datagram", "socket_name", "udp:IPADDRESS:8033")
# ----- rr params -----
# add value to ;lr param to cope with most of the UAs
modparam("rr", "enable_full_lr", 1)
# do not append from tag to the RR (no need for this script)
#!ifdef WITH_ASTERISK
modparam("rr", "append_fromtag", 1)
#!else
modparam("rr", "append_fromtag", 0)
#!endif
 
# ----- registrar params -----
modparam("registrar", "method_filtering", 1)
/* uncomment the next line to disable parallel forking via location */
# modparam("registrar", "append_branches", 0)
/* uncomment the next line not to allow more than 10 contacts per AOR */
#modparam("registrar", "max_contacts", 10)
# max value for expires of registrations
modparam("registrar", "max_expires", 3600)
# set it to 1 to enable GRUU
modparam("registrar", "gruu_enabled", 0)
 
 
# ----- acc params -----
/* what special events should be accounted ? */
modparam("acc", "early_media", 1)
modparam("acc", "report_ack", 1)
modparam("acc", "report_cancels", 0)
/* by default ww do not adjust the direct of the sequential requests.
   if you enable this parameter, be sure the enable "append_fromtag"
   in "rr" module */
modparam("acc", "detect_direction", 0)
/* account triggers (flags) */
modparam("acc", "log_flag", FLT_ACC)
modparam("acc", "log_missed_flag", FLT_ACCMISSED)
modparam("acc", "log_extra", 
	"src_user=$fU;src_domain=$fd;src_ip=$si;"
	"dst_ouser=$tU;dst_user=$rU;dst_domain=$rd")
modparam("acc", "failed_transaction_flag", FLT_ACCFAILED)
/* enhanced DB accounting */
#!ifdef WITH_ACCDB
modparam("acc", "db_flag", FLT_ACC)
modparam("acc", "db_missed_flag", FLT_ACCMISSED)
modparam("acc", "db_url", DBURL)
modparam("acc", "db_extra",
	"src_user=$fU;src_domain=$fd;src_ip=$si;"
	"dst_ouser=$tU;dst_user=$rU;dst_domain=$rd")

#modparam("acc", "cdr_enable", 1)
#modparam("acc", "cdr_start_on_confirmed", 1)
#modparam("acc", "cdr_start_id", "start")
#modparam("acc", "cdr_end_id", "end")
#modparam("acc", "cdr_duration_id", "d")
#modparam("acc", "cdr_log_enable", 1)
modparam("acc", "cdrs_table", "cdrs")
#!endif
 

 
# ----- usrloc params -----
/* enable DB persistency for location entries */
#!ifdef WITH_USRLOCDB
modparam("usrloc", "db_url", DBURL)
modparam("usrloc", "db_mode", 2)
modparam("usrloc", "use_domain", MULTIDOMAIN)
#!endif
 
 
# ----- auth_db params -----
#!ifdef WITH_AUTH
modparam("auth_db", "calculate_ha1", yes)
modparam("auth_db", "load_credentials", "")
 
#!ifdef WITH_ASTERISK
modparam("auth_db", "user_column", "username")
modparam("auth_db", "password_column", "sippasswd")
modparam("auth_db", "db_url", DBASTURL)
modparam("auth_db", "version_table", 0)
#!else
modparam("auth_db", "db_url", DBURL)
modparam("auth_db", "password_column", "password")
modparam("auth_db", "use_domain", MULTIDOMAIN)
#!endif
 
# ----- permissions params -----
#!ifdef WITH_IPAUTH
modparam("permissions", "db_url", DBURL)
modparam("permissions", "db_mode", 1)
#!endif
 
#!endif
 
 
# ----- alias_db params -----
#!ifdef WITH_ALIASDB
modparam("alias_db", "db_url", DBURL)
modparam("alias_db", "use_domain", MULTIDOMAIN)
#!endif
 
 
# ----- speedial params -----
#!ifdef WITH_SPEEDDIAL
modparam("speeddial", "db_url", DBURL)
modparam("speeddial", "use_domain", MULTIDOMAIN)
#!endif
 
 
# ----- domain params -----
#!ifdef WITH_MULTIDOMAIN
modparam("domain", "db_url", DBURL)
# register callback to match myself condition with domains list
modparam("domain", "register_myself", 1)
#!endif
 
 
#!ifdef WITH_PRESENCE
# ----- presence params -----
modparam("presence", "db_url", DBURL)
 
# ----- presence_xml params -----
modparam("presence_xml", "db_url", DBURL)
modparam("presence_xml", "force_active", 1)
#!endif
 
 
#!ifdef WITH_NAT
# ----- rtpproxy params -----
modparam("rtpproxy", "rtpproxy_sock", "udp:127.0.0.1:7722")
modparam("rtpproxy", "rtpproxy_disable_tout", 8)
modparam("rtpproxy", "rtpproxy_tout", 2)
 
# ----- nathelper params -----
modparam("nathelper", "natping_interval", 30)
modparam("nathelper", "ping_nated_only", 1)
modparam("nathelper", "sipping_bflag", FLB_NATSIPPING)
modparam("nathelper", "sipping_from", "sip:pinger@kamailio.org")
 
# params needed for NAT traversal in other modules
modparam("nathelper|registrar", "received_avp", "$avp(RECEIVED)")
modparam("usrloc", "nat_bflag", FLB_NATB)
#!endif
 
 
#!ifdef WITH_TLS
# ----- tls params -----
modparam("tls", "config", "/usr/local/etc/kamailio/tls.cfg")
#!endif
 
#!ifdef WITH_ANTIFLOOD
# ----- pike params -----
modparam("pike", "sampling_time_unit", 2)
modparam("pike", "reqs_density_per_unit", 16)
modparam("pike", "remove_latency", 4)
 
# ----- htable params -----
# ip ban htable with autoexpire after 5 minutes
modparam("htable", "htable", "ipban=>size=8;autoexpire=300;")
#!endif
 
#!ifdef WITH_XMLRPC
# ----- xmlrpc params -----
modparam("xmlrpc", "route", "XMLRPC");
modparam("xmlrpc", "url_match", "^/RPC")
#!endif
 
#!ifdef WITH_DEBUG
# ----- debugger params -----
modparam("debugger", "cfgtrace", 1)
#!endif
 
####### Routing Logic ########


# Main SIP request routing logic
# - processing of any incoming SIP request starts with this route
# - note: this is the same as route { ... }
request_route {
 
	# per request initial checks
	route(REQINIT);
 
	# NAT detection
	route(NATDETECT);
 
	# handle requests within SIP dialogs
	route(WITHINDLG);
 
	### only initial requests (no To tag)
 
	# CANCEL processing
	if (is_method("CANCEL"))
	{
		if (t_check_trans())
			t_relay();
		exit;
	}
 
	t_check_trans();
 
	# authentication
	route(AUTH);
 
	# record routing for dialog forming requests (in case they are routed)
	# - remove preloaded route headers
	remove_hf("Route");
	if (is_method("INVITE|SUBSCRIBE"))
		record_route();
 
	# account only INVITEs
	if (is_method("INVITE"))
	{
		setflag(FLT_ACC); # do accounting
	}
 
	# dispatch requests to foreign domains
	route(SIPOUT);
 
	### requests for my local domains
 
	# handle presence related requests
	route(PRESENCE);
 
	# handle registrations
	route(REGISTRAR);
 
	if ($rU==$null)
	{
		# request with no Username in RURI
		sl_send_reply("484","Address Incomplete");
		exit;
	}
 
	# dispatch destinations to PSTN
	route(PSTN);
 
	# user location service
	route(LOCATION);
 
	route(RELAY);
}
 
route[DISPATCH] {
        # round robin dispatching on gateways group '1'
      xlog("trying for dispatch");
        if (!ds_select_domain("1", "4")) {
          send_reply("404", "No destination");
          exit;
        }
        t_on_failure("RTF_DISPATCH");
	route(RELAY);
	exit;
}
# Sample failure route
failure_route[RTF_DISPATCH] {
	if (t_is_canceled()) {
		exit;
	}
	# next DST - only for 500 or local timeout
	if (t_check_status("500")
			or (t_branch_timeout() and !t_branch_replied()))
	{
		if(ds_next_dst())
		{
			t_on_failure("RTF_DISPATCH");
			route(RELAY);
			exit;
		}
	}
}

 
route[RELAY] {
 
	# enable additional event routes for forwarded requests
	# - serial forking, RTP relaying handling, a.s.o.
	if (is_method("INVITE|SUBSCRIBE")) {
		t_on_branch("MANAGE_BRANCH");
		t_on_reply("MANAGE_REPLY");
	}
	if (is_method("INVITE")) {
		t_on_failure("MANAGE_FAILURE");
	}
 
	if (!t_relay()) {
		sl_reply_error();
	}
	exit;
}
 
# Per SIP request initial checks
route[REQINIT] {
#!ifdef WITH_ANTIFLOOD
	# flood dection from same IP and traffic ban for a while
	# be sure you exclude checking trusted peers, such as pstn gateways
	# - local host excluded (e.g., loop to self)
	if(src_ip!=myself)
	{
		if($sht(ipban=>$si)!=$null)
		{
			# ip is already blocked
			xdbg("request from blocked IP - $rm from $fu (IP:$si:$sp)\n");
			exit;
		}
		if (!pike_check_req())
		{
			xlog("L_ALERT","ALERT: pike blocking $rm from $fu (IP:$si:$sp)\n");
			$sht(ipban=>$si) = 1;
			exit;
		}
	}
#!endif
 
	if (!mf_process_maxfwd_header("10")) {
		sl_send_reply("483","Too Many Hops");
		exit;
	}
 
	if(!sanity_check("1511", "7"))
	{
		xlog("Malformed SIP message from $si:$sp\n");
		exit;
	}
}
 
# Handle requests within SIP dialogs
route[WITHINDLG] {
	if (has_totag()) {
		# sequential request withing a dialog should
		# take the path determined by record-routing
		if (loose_route()) {
			if (is_method("BYE")) {
				setflag(FLT_ACC); # do accounting ...
				setflag(FLT_ACCFAILED); # ... even if the transaction fails
			}
			if ( is_method("ACK") ) {
				# ACK is forwarded statelessy
				route(NATMANAGE);
			}
			route(RELAY);
		} else {
			if (is_method("SUBSCRIBE") && uri == myself) {
				# in-dialog subscribe requests
				route(PRESENCE);
				exit;
			}
			if ( is_method("ACK") ) {
				if ( t_check_trans() ) {
					# no loose-route, but stateful ACK;
					# must be an ACK after a 487
					# or e.g. 404 from upstream server
					t_relay();
					exit;
				} else {
					# ACK without matching transaction ... ignore and discard
					exit;
				}
			}
			sl_send_reply("404","Not here");
		}
		exit;
	}
}
 
# Handle SIP registrations
route[REGISTRAR] {
	if (is_method("REGISTER"))
	{
		if(isflagset(FLT_NATS))
		{
			setbflag(FLB_NATB);
			# uncomment next line to do SIP NAT pinging 
			## setbflag(FLB_NATSIPPING);
		}
		if (!save("location"))
			sl_reply_error();
 
#!ifdef WITH_ASTERISK
		route(REGFWD);
#!endif
 
		exit;
	}
}
 
# USER location service
route[LOCATION] {
 
#!ifdef WITH_SPEEDIAL
	# search for short dialing - 2-digit extension
	if($rU=~"^[0-9][0-9]$")
		if(sd_lookup("speed_dial"))
			route(SIPOUT);
#!endif
 
#!ifdef WITH_ALIASDB
	# search in DB-based aliases
	if(alias_db_lookup("dbaliases"))
		route(SIPOUT);
#!endif
 
#!ifdef WITH_ASTERISK
	if(is_method("INVITE") && (!route(FROMASTERISK))) {
		# if new call from out there - send to Asterisk
		# - non-INVITE request are routed directly by Kamailio
		# - traffic from Asterisk is routed also directy by Kamailio
		route(TOASTERISK);
		exit;
	}
#!endif
 
	$avp(oexten) = $rU;
	if (!lookup("location")) {
		$var(rc) = $rc;
		route(TOVOICEMAIL);
		t_newtran();
		switch ($var(rc)) {
			case -1:
			case -3:
				send_reply("404", "Not Found");
				exit;
			case -2:
				send_reply("405", "Method Not Allowed");
				exit;
		}
	}
 
	# when routing via usrloc, log the missed calls also
	if (is_method("INVITE"))
	{
		setflag(FLT_ACCMISSED);
	}
}
 
# Presence server route
route[PRESENCE] {
	if(!is_method("PUBLISH|SUBSCRIBE"))
		return;
 
#!ifdef WITH_PRESENCE
	if (!t_newtran())
	{
		sl_reply_error();
		exit;
	};
 
	if(is_method("PUBLISH"))
	{
		handle_publish();
		t_release();
	}
	else
	if( is_method("SUBSCRIBE"))
	{
		handle_subscribe();
		t_release();
	}
	exit;
#!endif
 
	# if presence enabled, this part will not be executed
	if (is_method("PUBLISH") || $rU==$null)
	{
		sl_send_reply("404", "Not here");
		exit;
	}
	return;
}
 
# Authentication route
route[AUTH] {
#!ifdef WITH_AUTH
 
#!ifdef WITH_ASTERISK
	# do not auth traffic from Asterisk - trusted!
	if(route(FROMASTERISK))
		return;
#!endif
 
#!ifdef WITH_IPAUTH
	if((!is_method("REGISTER")) && allow_source_address())
	{
		# source IP allowed
		return;
	}
#!endif
 
	if (is_method("REGISTER") || from_uri==myself)
	{
		# authenticate requests
#!ifdef WITH_ASTERISK
		if (!auth_check("$fd", "sipusers", "1")) {
#!else
		if (!auth_check("$fd", "subscriber", "1")) {
#!endif
			auth_challenge("$fd", "0");
			exit;
		}
		# user authenticated - remove auth header
		if(!is_method("REGISTER|PUBLISH"))
			consume_credentials();
	}
	# if caller is not local subscriber, then check if it calls
	# a local destination, otherwise deny, not an open relay here
	if (from_uri!=myself && uri!=myself)
	{
		sl_send_reply("403","Not relaying");
		exit;
	}
 
#!endif
	return;
}
 
# Caller NAT detection route
route[NATDETECT] {
#!ifdef WITH_NAT
	force_rport();
	if (nat_uac_test("19")) {
		if (is_method("REGISTER")) {
			fix_nated_register();
		} else {
			fix_nated_contact();
		}
		setflag(FLT_NATS);
	}
#!endif
	return;
}


route[RTPPROXY] {
        if (is_method("INVITE")){
                sql_query("ca", "select destination from dispatcher where destination like '%$dd%'","ra");
                if($dbr(ra=>rows)>0){
                        $avp(duip)=$(du{s.select,-2,:});
                        if (is_ip_rfc1918("$avp(duip)")) {
                                xlog("L_INFO", "Call is going to private IPv4 Media Server Engage RTPProxy Now\n");
                               
                                rtpproxy_manage("rwie");
                        }

                }
                else if(ds_is_from_list()){
                        if (is_ip_rfc1918("$si")) {
                                xlog("L_INFO", " Call is coming from a private IPv4 Media Server Engage RTPProxy Now\n");
                                
                                rtpproxy_manage("rwei");

                        }
                }else if(!ds_is_from_list()){
                          rtpproxy_manage("rwie");

                }
      }

}


# RTPProxy control
route[NATMANAGE] {
#!ifdef WITH_NAT
	if (is_request()) {
		if(has_totag()) {
			if(check_route_param("nat=yes")) {
				setbflag(FLB_NATB);
			}
		}
	}
 if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))){
                return;
        }
                
	
 
	rtpproxy_manage();
 
	if (is_request()) {
		if (!has_totag()) {
			add_rr_param(";nat=yes");
		}
	}
	if (is_reply()) {
		if(isbflagset(FLB_NATB)) {
			fix_nated_contact();
		}
	}
#!endif
	return;
}
 
# Routing to foreign domains
route[SIPOUT] {
	if (!uri==myself)
	{
		append_hf("P-hint: outbound\r\n");
		route(RELAY);
	}
}
 
# PSTN GW routing
route[PSTN] {
#!ifdef WITH_PSTN
	# check if PSTN GW IP is defined
	if (strempty($sel(cfg_get.pstn.gw_ip))) {
		xlog("SCRIPT: PSTN rotuing enabled but pstn.gw_ip not defined\n");
		return;
	}
 
	# route to PSTN dialed numbers starting with '+' or '00'
	#     (international format)
	# - update the condition to match your dialing rules for PSTN routing
	if(!($rU=~"^(\+|00)[1-9][0-9]{3,20}$"))
		return;
 
	# only local users allowed to call
	if(from_uri!=myself) {
		sl_send_reply("403", "Not Allowed");
		exit;
	}
 
	$ru = "sip:" + $rU + "@" + $sel(cfg_get.pstn.gw_ip);
 
	route(RELAY);
	exit;
#!endif
 
	return;
}
 
# XMLRPC routing
#!ifdef WITH_XMLRPC
route[XMLRPC] {
	# allow XMLRPC from localhost
	if ((method=="POST" || method=="GET")
			&& (src_ip==127.0.0.1)) {
		# close connection only for xmlrpclib user agents (there is a bug in
		# xmlrpclib: it waits for EOF before interpreting the response).
		if ($hdr(User-Agent) =~ "xmlrpclib")
			set_reply_close();
		set_reply_no_connect();
		dispatch_rpc();
		exit;
	}
	send_reply("403", "Forbidden");
	exit;
}
#!endif
 
# route to voicemail server
route[TOVOICEMAIL] {
#!ifdef WITH_VOICEMAIL
	if(!is_method("INVITE"))
		return;
 
	# check if VoiceMail server IP is defined
	if (strempty($sel(cfg_get.voicemail.srv_ip))) {
		xlog("SCRIPT: VoiceMail rotuing enabled but IP not defined\n");
		return;
	}
	if($avp(oexten)==$null)
		return;
 
	$ru = "sip:" + $avp(oexten) + "@" + $sel(cfg_get.voicemail.srv_ip)
				+ ":" + $sel(cfg_get.voicemail.srv_port);
	route(RELAY);
	exit;
#!endif
 
	return;
}
 
# manage outgoing branches
branch_route[MANAGE_BRANCH] {
	xdbg("new branch [$T_branch_idx] to $ru\n");
	route(NATMANAGE);
}
 
# manage incoming replies
onreply_route[MANAGE_REPLY] {
	xdbg("incoming reply\n");
	if(status=~"[12][0-9][0-9]")
		route(NATMANAGE);
}
 
# manage failure routing cases
failure_route[MANAGE_FAILURE] {
	route(NATMANAGE);
 
	if (t_is_canceled()) {
		exit;
	}
 
#!ifdef WITH_BLOCK3XX
	# block call redirect based on 3xx replies.
	if (t_check_status("3[0-9][0-9]")) {
		t_reply("404","Not found");
		exit;
	}
#!endif
 
#!ifdef WITH_VOICEMAIL
	# serial forking
	# - route to voicemail on busy or no answer (timeout)
	if (t_check_status("486|408")) {
		route(TOVOICEMAIL);
		exit;
	}
#!endif
}
 
#!ifdef WITH_ASTERISK
# Test if coming from Asterisk
route[FROMASTERISK] {
   if(ds_is_from_list()){
        
        return 1;
   }
 return -1;
}
 
route[TOASTERISK] {
        ds_mark_dst("P");
        if(!ds_select_dst("1", "9")) {
                sl_send_reply("500", "Service Unavailable");
                
                exit;
        }

          

 route(RELAY);
 exit;
}
 
 
# Forward REGISTER to Asterisk
route[REGFWD] {
	if(!is_method("REGISTER"))
	{
		return;
	}
	$var(rip) = $sel(cfg_get.asterisk.bindip);
	$uac_req(method)="REGISTER";
	$uac_req(ruri)="sip:" + $var(rip) + ":" + $sel(cfg_get.asterisk.bindport);
	$uac_req(furi)="sip:" + $au + "@" + $var(rip);
	$uac_req(turi)="sip:" + $au + "@" + $var(rip);
	$uac_req(hdrs)="Contact: <sip:" + $au + "@"
				+ $sel(cfg_get.kamailio.bindip)
				+ ":" + $sel(cfg_get.kamailio.bindport) + ">\r\n";
	if($sel(contact.expires) != $null)
		$uac_req(hdrs)= $uac_req(hdrs) + "Expires: " + $sel(contact.expires) + "\r\n";
	else
		$uac_req(hdrs)= $uac_req(hdrs) + "Expires: " + $hdr(Expires) + "\r\n";
	uac_req_send();
}
#!endif

回答1:

You'll want to use the Kamailio dispatcher module.

You'll have a dispatcher.list like:

# group  sip addresses of your asterisk boxen
1 sip:10.1.2.3:5060
1 sip:10.1.2.4:5060
1 sip:10.1.2.5:5060

And a kamailio.cfg configured like so:

loadmodule("dispatcher.so")

...

if ( method=="INVITE" ) {
# dst_select( "GROUP", "HASH METHOD")
  ds_select_dst("1","4");
  sl_send_reply("100","Trying");
  forward();#uri:host, uri:port);
  exit();
}

Additionally, kamailio has an example in their wiki. And you can also find more about the dispatcher for Kamailio 4.3 in the docs.

p.s. Stackexchange tip: You'll get more replies if you're willing to document the steps you've tried, and posting your specific configurations and explaining what did and didn't work, as opposed to a general overview.

---

Checking the health of dispatched Asterisk boxes. To route-advance when an Asterisk box is down. You should check the health of the boxes. You can also do this using the dispatcher. This should also a take a box out of rotation when issue a command such as core shutdown gracefully which will make asterisk start responding with a 'not available' response.

modparam("dispatcher", "ds_probing_mode", 1)
modparam("dispatcher", "ds_ping_interval", 15)
modparam("dispatcher", "ds_probing_threshold", 1)
modparam("dispatcher", "ds_ping_reply_codes", "class=2;class=3;class=4")

回答2:

Add four records per asterisk server to your DNS: asterisk A 10.1.1.1 asterisk A 10.1.1.2 asterisk A 10.1.1.3 asterisk A 10.1.1.4 Setup your kamalio to use DNS asterisk.localdomain as address of asterisk trunk. DNS server will use "round robin" algorithm - next A address for each request.

来源：https://stackoverflow.com/questions/29312037/how-to-configure-kamailio-server-with-load-balancing-and-asterisk