Kamailio for masking Contact

Kamailio for masking SIP Contact field

André Guimarães, 2012-02-07

Switzernet

This document describes the installation and configuration procedure of a Kamailio machine which will be used to remove the username from the Contact URI field of each reply packet sent to a customer with the problem described in these documents:

http://ftp.switzernet.com/3/public/120106-dnatproblem/

http://ftp.switzernet.com/3/public/120131-outgoing-packets-interception/

Installation

Execute the following commands as root, in a machine with Debian Lenny installed, to add to Kamailio to the repository and install all required packages for this installation.

wget http://deb.kamailio.org/kamailiodebkey.gpg

apt-key add kamailiodebkey.gpg

echo -e "\n\nhttp://deb.kamailio.org/kamailio lenny main\ndeb-src http://deb.kamailio.org/kamailio lenny main" >> /etc/apt/sources.list

apt-get update

apt-get install rtpproxy kamailio kamailio-mysql-modules kamailio-geoip-modules kamailio-nth kamailio-utils-modules

Optionally MySQL can be also installed for future use. The procedure described here will assume a Database will be installed and used:

apt-get install mysql-server-5.1

Choose MySQL root pass when asked.

Configuration

Backup all original configuration files:

cp /etc/kamailio/kamailio.cfg /etc/kamailio/kamailio.cfg.original

cp /etc/kamailio/kamctlrc /etc/kamailio/kamctlrc.orginal

cp /etc/default/kamailio /etc/default/kamailio.original

Enable Kamailio :

sed -i -r 's/RUN_KAMAILIO.*/RUN_KAMAILIO=yes/g' /etc/default/kamailio

Edit Kamailio auto-configuration file and replace all content by the following:

DBENGINE=MYSQL

DBHOST=localhost

DBNAME=openser

DBRWUSER=openser

DBRWPW="openserrw"

DBROUSER=openserro

DBROPW=openserro

DBROOTUSER="root"

INSTALL_EXTRA_TABLES=ask

INSTALL_PRESENCE_TABLES=ask

CTLENGINE="FIFO"

OSER_FIFO="/tmp/kamailio_fifo"

To create all tables required automatically run:

kamdbctl create

Create a /etc/kamailio/kamailio.cfg.1 file with the following content. Differences to the original configuration file are marked in bold red:

#!KAMAILIO

# Kamailio (OpenSER) SIP Server v3.2 - default configuration script

# - web: http://www.kamailio.org

# - git: http://sip-router.org

# Direct your questions about this file to: <sr-users@lists.sip-router.org>

# Refer to the Core CookBook at http://www.kamailio.org/dokuwiki/doku.php

# for an explanation of possible statements, functions and parameters.

# Several features can be enabled using '#!define WITH_FEATURE' directives:

# *** To run in debug mode:

# - define WITH_DEBUG

# *** To enable mysql:

# - define WITH_MYSQL

# *** To enable authentication execute:

# - enable mysql

# - define WITH_AUTH

# - add users using 'kamctl'

# *** To enable IP authentication execute:

# - enable mysql

# - enable authentication

# - define WITH_IPAUTH

# - add IP addresses with group id '1' to 'address' table

# *** To enable persistent user location execute:

# - enable mysql

# - define WITH_USRLOCDB

# *** To enable presence server execute:

# - enable mysql

# - define WITH_PRESENCE

# *** To enable nat traversal execute:

# - define WITH_NAT

# - install RTPProxy: http://www.rtpproxy.org

# - start RTPProxy:

# rtpproxy -l _your_public_ip_ -s udp:localhost:7722

# *** To enable PSTN gateway routing execute:

# - define WITH_PSTN

# - set the value of pstn.gw_ip

# - check route[PSTN] for regexp routing condition

# *** To enable database aliases lookup execute:

# - enable mysql

# - define WITH_ALIASDB

# *** To enable speed dial lookup execute:

# - enable mysql

# - define WITH_SPEEDDIAL

# *** To enable multi-domain support execute:

# - enable mysql

# - define WITH_MULTIDOMAIN

# *** To enable TLS support execute:

# - adjust CFGDIR/tls.cfg as needed

# - define WITH_TLS

# *** To enable XMLRPC support execute:

# - define WITH_XMLRPC

# - adjust route[XMLRPC] for access policy

# *** To enable anti-flood detection execute:

# - adjust pike and htable=>ipban settings as needed (default is

# block if more than 16 requests in 2 seconds and ban for 300 seconds)

# - define WITH_ANTIFLOOD

# *** To block 3XX redirect replies execute:

# - define WITH_BLOCK3XX

# *** To enable VoiceMail routing execute:

# - define WITH_VOICEMAIL

# - set the value of voicemail.srv_ip

# - adjust the value of voicemail.srv_port

# *** To enhance accounting execute:

# - enable mysql

# - define WITH_ACCDB

# - add following columns to database

#!ifdef ACCDB_COMMENT

ALTER TABLE acc ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE acc ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT '';

ALTER TABLE acc ADD COLUMN src_ip varchar(64) NOT NULL default '';

ALTER TABLE acc ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE acc ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE acc ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT '';

ALTER TABLE missed_calls ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE missed_calls ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT '';

ALTER TABLE missed_calls ADD COLUMN src_ip varchar(64) NOT NULL default '';

ALTER TABLE missed_calls ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE missed_calls ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT '';

ALTER TABLE missed_calls ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT '';

#!endif

####### Defined Values #########

###!define WITH_DEBUG

#!define WITH_ANTIFLOOD

#!define WITH_NAT

# *** 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://openser:openserrw@localhost/openser"

#!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=2

log_stderror=no

#!endif

memdbg=5

memlog=5

log_facility=LOG_LOCAL0

fork=yes

children=4

/* uncomment the next line to disable TCP (default on) */

#disable_tcp=yes

/* uncomment the next line to disable the auto discovery of local aliases

based on reverse DNS on IPs (default on) */

#auto_aliases=no

/* add local domain aliases */

#alias="sip.mydomain.com"

/* uncomment and configure the following line if you want Kamailio to

bind on a specific interface/port/proto (default bind on all available) */

#listen=udp:10.0.0.10:5060

/* port to listen to

* - can be specified more than once if needed to listen on many ports */

port=5060

#!ifdef WITH_TLS

enable_tls=yes

#!endif

# life time of TCP connection when there is no traffic

# - a bit higher than registration expires to cope with UA behind NAT

tcp_connection_lifetime=3605

####### Custom Parameters #########

# These parameters can be modified runtime via RPC interface

# - see the documentation of 'cfg_rpc' module.

# Format: group.id = value 'desc' description

# Access: $sel(cfg_get.group.id) or @cfg_get.group.id

#!ifdef WITH_PSTN

# PSTN GW Routing

# - pstn.gw_ip: valid IP or hostname as string value, example:

# pstn.gw_ip = "10.0.0.101" desc "My PSTN GW Address"

# - by default is empty to avoid misrouting

pstn.gw_ip = "" desc "PSTN GW Address"

#!endif

#!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

####### Modules Section ########

# set paths to location of modules (to sources or installation folders)

#!ifdef WITH_SRCPATH

mpath="modules_k:modules"

#!else

mpath="/usr/lib64/kamailio/modules_k/:/usr/lib64/kamailio/modules/"

#!endif

#!ifdef WITH_MYSQL

loadmodule "db_mysql.so"

#!endif

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"

#!ifdef WITH_AUTH

loadmodule "auth.so"

loadmodule "auth_db.so"

#!ifdef WITH_IPAUTH

loadmodule "permissions.so"

#!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

# ----------------- 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)

# ----- 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)

modparam("rr", "append_fromtag", 0)

# ----- 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)

# ----- acc params -----

/* what special events should be accounted ? */

modparam("acc", "early_media", 0)

modparam("acc", "report_ack", 0)

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")

#!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", "db_url", DBURL)

modparam("auth_db", "calculate_ha1", yes)

modparam("auth_db", "password_column", "password")

modparam("auth_db", "load_credentials", "")

modparam("auth_db", "use_domain", MULTIDOMAIN)

# ----- permissions params -----

#!ifdef WITH_IPAUTH

modparam("permissions", "db_url", DBURL)

modparam("permissions", "db_mode", 1)

#!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)

# use caching

modparam("domain", "db_mode", 1)

# 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")

# ----- 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", "/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); #Disable this block to prevent it from intercepting our calls

$ru = "sip:" + $rU + "@" + $fd; # Redirect the packet to the server from where we received the call request

$td = $fd; # Mask the to domain to the Astrad from where the request was received

$tn = $tU; # Mask the TO CallerID to the number called (the previous value is “Transfer”)

append_hf("X-Astrad-Relay: 1\r\n"); # Append an Header to mark the call as redirected to avoid second redirection in the Astrad

route(RELAY);

}

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();

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

$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

if (is_method("REGISTER"))

{

# authenticate the REGISTER requests (uncomment to enable auth)

if (!www_authorize("$td", "subscriber"))

{

www_challenge("$td", "0");

exit;

}

if ($au!=$tU)

{

sl_send_reply("403","Forbidden auth ID");

exit;

}

} else {

#!ifdef WITH_IPAUTH

if(allow_source_address())

{

# source IP allowed

return;

}

#!endif

# authenticate if from local subscriber

if (from_uri==myself)

{

if (!proxy_authorize("$fd", "subscriber")) {

proxy_challenge("$fd", "0");

exit;

}

if (is_method("PUBLISH"))

{

if ($au!=$fU || $au!=$tU) {

sl_send_reply("403","Forbidden auth ID");

exit;

}

if ($au!=$rU) {

sl_send_reply("403","Forbidden R-URI");

exit;

}

#!ifdef WITH_MULTIDOMAIN

if ($fd!=$rd) {

sl_send_reply("403","Forbidden R-URI domain");

exit;

}

#!endif

} else {

if ($au!=$fU) {

sl_send_reply("403","Forbidden auth ID");

exit;

}

consume_credentials();

# caller authenticated

} else {

# caller is not local subscriber, then check if it calls

# a local destination, otherwise deny, not an open relay here

if (!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;

}

# 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");

subst('/^Contact:(.*):.*@(.*)$/Contact:\1:\2/ig'); # Remove number from Contact

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

}

Verify if the configuration file as errors:

kamailio –c /etc/kamailio/kamailio.cfg.1

which should result in :

loading modules under /usr/lib64/kamailio/modules_k/:/usr/lib64/kamailio/modules/

Listening on

…

udp: localhost:5060

udp: localhost.localdomain:5060

config file ok, exiting...

If there are no errors replace the configuration file by the modified one. Then restart Kamailio:

cp /etc/kamailio/kamailio.cfg.1 /etc/kamailio/kamailio.cfg

/etc/init.d/kamailio restart

References:

http://ftp.switzernet.com/3/public/120106-dnatproblem/

http://ftp.switzernet.com/3/public/120131-outgoing-packets-interception/

http://sip-router.org/wiki/cookbooks/pseudo-variables/devel