[Serusers] could not pass the audio through NAT for the SIP client.

C.K ckng128 at yahoo.com
Tue Aug 10 15:48:57 CEST 2004


Hello,

I have try to identify this problem for long time but
still do not have any idea where is the problem, could
some one point it out here please.

I have the asterisk and SER behind a NAT (at office)
and both UA are also behind another NAT (at home), I
could hear the echo test from asterisk when I am using
the port farwading BUT doesn't have any audio when I
disable the port forwading..please help..

My Sip.cfg and sip.conf are as follow:

# ------------------- global configuration parameters
------------------------

#debug=3         # debug level (cmd line: -dddddddddd)
#fork=yes
#log_stderror=no # (cmd line: -E)

#debug=7
#fork=no
#log_stderror=yes

check_via=no    # (cmd. line: -v)
dns=no           # (cmd. line: -r)
rev_dns=no      # (cmd. line: -R)
port=5060
children=4
fifo="/tmp/ser_fifo"

alias=detone
alias=detone.ghl.com
alias=202.129.171.223
# ------------------- module loading
------------------
loadmodule "/usr/local/lib/ser/modules/sl.so"
loadmodule "/usr/local/lib/ser/modules/tm.so"
loadmodule "/usr/local/lib/ser/modules/rr.so"
loadmodule "/usr/local/lib/ser/modules/maxfwd.so"
loadmodule "/usr/local/lib/ser/modules/usrloc.so"
loadmodule "/usr/local/lib/ser/modules/registrar.so"
loadmodule "/usr/local/lib/ser/modules/exec.so"
loadmodule "/usr/local/lib/ser/modules/xlog.so"
#loadmodule "/usr/local/lib/ser/modules/mysql.so"
#loadmodule "/usr/local/lib/ser/modules/auth.so"
#loadmodule "/usr/local/lib/ser/modules/auth_db.so"
loadmodule "/usr/local/lib/ser/modules/nathelper.so"
loadmodule "/usr/local/lib/ser/modules/textops.so"
# ----------------- setting module-specific parameters
---------------
modparam("usrloc", "db_mode", 0)
#modparam("auth_db", "calculate_ha1", yes)
#modparam("auth_db", "password_column", "password")

modparam("rr", "enable_full_lr", 1)

# ------------------ NAThelper ----------------
modparam("registrar", "nat_flag", 6)
modparam("nathelper", "natping_interval", 30) # Ping
interval 30 s
modparam("nathelper", "ping_nated_only", 1)   # Ping
only clients behind NAT

# -------------------------  request routing logic
-------------------
route{

        # initial sanity checks -- messages with
        # max_forwards==0, or excessively long
requests

        if (!mf_process_maxfwd_header("10")) {
                sl_send_reply("483","Too Many Hops");
                break;
        };
        if ( msg:len > max_len ) {
                sl_send_reply("513", "Message too
big");
                break;
        };

	# Special handling for NATed clients; first, NAT test
is
        # executed: it looks for via!=received and
RFC1918 addresses
        # in Contact (may fail if line-folding is
used); also, 
        # the received test should, if completed,
should check all
        # vias for rpesence of received
	xlog("L_NOTICE", "Checking...behind the NAT ?\n");
	if (nat_uac_test("1")) {
		xlog("L_NOTICE", "nat_uac_test=1\n");
	}
	if (nat_uac_test("2")) {
		xlog("L_NOTICE", "nat_uac_test=2\n");
	}
        if (nat_uac_test("3")) {
		xlog("L_NOTICE", "nat_uac_test == 3\n");
                # Allow RR-ed requests, as these may
indicate that
                # a NAT-enabled proxy takes care of
it; unless it is
                # a REGISTER
                
                if (method == "REGISTER" || !
search("^Record-Route:")) { 
                    xlog("L_NOTICE", "Someone trying
to register from private IP, rewriting\n");

                    # This will work only for user
agents that support symmetric
                    # communication. We tested quite
many of them and majority is
                    # smart enough to be symmetric. In
some phones it takes a configuration
                    # option. With Cisco 7960, it is
called NAT_Enable=Yes, with kphone it is
                    # called "symmetric media" and
"symmetric signalling".
                    
                    fix_nated_contact(); # Rewrite
contact with source IP of signalling
                    if (method == "INVITE") { 
			xlog("L_NOTICE", "invite behind NAT.\n");
                        fix_nated_sdp("1"); # Add
direction=active to SDP
                    };
                    force_rport(); # Add rport
parameter to topmost Via
                    setflag(6);    # Mark as NATed
                };
        };
 
	# we record-route all messages -- to make sure that
        # subsequent messages will go through our
proxy; that's
        # particularly good if upstream and downstream
entities
        # use different transport protocol
        record_route();
 
        # loose-route processing
        if (loose_route()) {
		xlog("L_NOTICE", "loose route.\n");
	#	append_hf("P-hint: rr-enforced\r\n");
                t_relay();
                break;
        };

/*
        if
(uri=~"^sip:[0-9][0-9][0-9]*@202.129.171.223") {
		xlog("L_NOTICE", "forward to asterisk.\n");
                forward(10.38.38.14, 5070);
                break;
        };
*/


	if (uri =~ "sip:[0-9][0-9][0-9]*@*"){
           xlog("L_NOTICE", "Forwarding to
Asterisk\n");
           rewritehostport("10.38.38.14:5070");
           t_relay();
           break;
 	};

	# if the request is for other domain use UsrLoc
        # (in case, it does not work, use the
following command
        # with proper names and addresses in it)

	xlog("L_NOTICE", "uri==myself?\n");
	if (uri==myself){

           if (method=="REGISTER") {
	      xlog("L_NOTICE", "register but no NAT.\n");
              sl_send_reply("200", "ok");
              save("location");
              break;
            };

            # native SIP destinations are handled
using our USRLOC DB
            xlog("L_NOTICE", "lookup for USRLOC.\n");
            if (!lookup("location")) {
                sl_send_reply("404", "Not Found");
              #  break;
            };
        };

	xlog("L_NOTICE", "checking....INVITE\n");
        if (method == "INVITE") {
	  xlog("L_NOTICE", "Invite from not NAT.\n");
          record_route();
	  if (isflagset(4) && isflagset(5)) {
             xlog("L_NOTICE", "UA behind different NAT
devices, forcing rtpproxy\n");
             force_rtp_proxy();
             t_on_reply("2");
          } else {
             xlog("L_NOTICE", "UAs behind same NAT
devicea\n");
             t_on_reply("3");
          }
# for other conditions route here...
        }

        # forward to current uri now; use stateful
forwarding; that
        # works reliably even if we forward from TCP
to UDP
        if (!t_relay()) {
           sl_reply_error();
        };

}

onreply_route[1] {
  if (status =~ "[12][0-9][0-9]"){
      fix_nated_contact();
      force_rtp_proxy();
  }
}


onreply_route[2] {
  if (status == "200" || status == "183"){
     if (isflagset(5)) {
         fix_nated_contact();
      };
      force_rtp_proxy();
  }
}

onreply_route[3] {
  if (status == "200" || status == "183"){
     if (isflagset(5)) {
         fix_nated_contact();
      };
      force_rtp_proxy();
  }
}


************************* end of ser.cfg
;
; SIP Configuration for Asterisk
;
; Syntax for specifying a SIP device in
extensions.conf is
; SIP/devicename where devicename is defined in a
section below.
;
; You may also use 
; SIP/username at domain to call any SIP user on the
Internet
; (Don't forget to enable DNS SRV records if you want
to use this)
; 
; If you define a SIP proxy as a peer below, you may
call
; SIP/proxyhostname/user or SIP/user at proxyhostname 
; where the proxyhostname is defined in a section
below 
; 
; Useful CLI commands to check peers/users:
;   sip show peers		Show all SIP peers (including
friends)
;   sip show users		Show all SIP users (including
friends)
;   sip show registry		Show status of hosts we
register with
;
;   sip debug			Show all SIP messages
;

[general]
context=default			; Default context for incoming calls
;recordhistory=yes		; Record SIP history by default 
				; (see sip history / sip no history)
;realm=mydomain.tld		; Realm for digest authentication
				; defaults to "asterisk"
				; Realms MUST be globally unique according to RFC
3261
				; Set this to your host name or domain name
port=5070			; UDP Port to bind to (SIP standard port
is 5060)
bindaddr=0.0.0.0		; IP address to bind to (0.0.0.0
binds to all)
srvlookup=yes			; Enable DNS SRV lookups on outbound
calls
				; Note: Asterisk only uses the first host 
				; in SRV records
				; Disabling DNS SRV lookups disables the 
				; ability to place SIP calls based on domain 
				; names to some other SIP users on the Internet
				
;pedantic=yes			; Enable slow, pedantic checking for
Pingtel
				; and multiline formatted headers for strict
				; SIP compatibility (defaults to "no")
;tos=184                        ; Set IP QoS to either
a keyword or numeric val
;tos=lowdelay                   ;
lowdelay,throughput,reliability,mincost,none
;maxexpirey=3600		; Max length of incoming
registration we allow
;defaultexpirey=120		; Default length of
incoming/outoing registration
;notifymimetype=text/plain	; Allow overriding of mime
type in MWI NOTIFY
;videosupport=yes		; Turn on support for SIP video

;disallow=all			; First disallow all codecs
;allow=ulaw			; Allow codecs in order of preference
;allow=ilbc			; Note: codec order is respected only in
[general]
;musicclass=default		; Sets the default music on hold
class for all SIP calls
				; This may also be set for individual users/peers
;language=en			; Default language setting for all
users/peers
				; This may also be set for individual users/peers
;relaxdtmf=yes			; Relax dtmf handling
;rtptimeout=60			; Terminate call if 60 seconds of no
RTP activity
				; when we're not on hold
;rtpholdtimeout=300		; Terminate call if 300 seconds
of no RTP activity
				; when we're on hold (must be > rtptimeout)
;trustrpid = no			; If Remote-Party-ID should be
trusted
;progressinband=no		; If we should generate in-band
ringing always
;useragent=Asterisk PBX		; Allows you to change the
user agent string
;nat=no				; NAT settings 
                                ; yes = Always ignore
info and assume NAT
                                ; no = Use NAT mode
only according to RFC3581 
                                ; never = Never
attempt NAT mode or RFC3581 support
;promiscredir = no      ; If yes, allows 302 or REDIR
to non-local SIP address
; Asterisk can register as a SIP user agent to a SIP
proxy (provider)
; Format for the register statement is:
;       register =>
user[:secret[:authuser]]@host[:port][/extension]
;
; If no extension is given, the 's' extension is used.
The extension
; needs to be defined in extensions.conf to be able to
accept calls
; from this SIP proxy (provider)
;
; host is either a host name defined in DNS or the
name of a 
; section defined below.
;
; Examples:
;
;register => 1234:password at mysipprovider.com	
;
;     This will pass incoming calls to the 's'
extension
;
;
;register => 2345:password at sip_proxy/1234
;
;    Register 2345 at sip provider 'sip_proxy'.  Calls
from this provider connect to local 
;    extension 1234 in extensions.conf default
context, unless you define 
;    unless you configure a [sip_proxy] section below,
and configure a context.
;	 Tip 1: Avoid assigning hostname to a sip.conf
section like [provider.com]
;        Tip 2: Use separate type=peer and type=user
sections for SIP providers
;                      (instead of type=friend) if you
have calls in both directions
  

;externip = 200.201.202.203	; Address that we're going
to put in outbound SIP messages
				; if we're behind a NAT

				; The externip and localnet is used
				; when registering and communicating with other
proxies
				; that we're registered with
				; You may add multiple local networks.  A
reasonable set of defaults
				; are:
;localnet=192.168.0.0/255.255.0.0; All RFC 1918
addresses are local networks
;localnet=10.0.0.0/255.0.0.0	; Also RFC1918
;localnet=172.16.0.0/12		; Another RFC1918 with CIDR
notation
;localnet=169.254.0.0/255.255.0.0 ;Zero conf local
network

;-----------------------------------------------------------------------------------
; Users and peers have different settings available.
Friends have all settings,
; since a friend is both a peer and a user
;
; User config options:        Peer configuration:
; --------------------        -------------------
; context                     context
; permit                      permit
; deny                        deny
; auth                        auth
; secret                      secret
; md5secret                   md5secret
; dtmfmode                    dtmfmode
; canreinvite                 canreinvite
; nat                         nat
; callgroup                   callgroup
; pickupgroup                 pickupgroup
; language                    language
; allow                       allow
; disallow                    disallow
; insecure                    insecure
; trustrpid                   trustrpid
; progressinband              progressinband
; promiscredir                promiscredir
; callerid
; accountcode
; amaflags
; incominglimit
; restrictcid
;                             mailbox
;                             username
;                             template
;                             fromdomain
;                             fromuser
;                             host
;                             mask
;                             port
;                             qualify
;                             defaultip
;                             rtptimeout
;                             rtpholdtimeout

;[sip_proxy]
; For incoming calls only. Example: FWD (Free World
Dialup)
;type=user
;context=from-fwd

;[sip_proxy-out]
;type=peer          		; we only want to call out, not
be called
;secret=guessit
;username=yourusername		; Authentication user for
outbound proxies
;fromuser=yourusername		; Many SIP providers require
this!
;host=box.provider.com

;[grandstream1]
;type=friend 			; either "friend" (peer+user), "peer"
or "user"
;context=from-sip
;fromuser=grandstream1		; overrides the callerid, e.g.
required by FWD
;callerid=John Doe <1234>
;host=192.168.0.23		; we have a static but private IP
address
;nat=no				; there is not NAT between phone and
Asterisk
;canreinvite=yes		; allow RTP voice traffic to bypass
Asterisk
;dtmfmode=info			; either RFC2833 or INFO for the
BudgeTone
;incominglimit=1		; permit only 1 outgoing call at a
time
				; from the phone to asterisk

[1008]
type=friend
username=1008
transfer=yes
context=default
fromuser=1008
callerid=
host=dynamic
nat=yes
canreinvite=yes
dtmfmode=info
;incominglimit=1

[1068]
type=friend
username=1068
transfer=yes
context=default
fromuser=1018
callerid=
host=dynamic
nat=yes
canreinvite=no
;dtmfmode=info
;incominglimit=1

mailbox=1234 at default  ; mailbox 1234 in voicemail
context "default"
disallow=all			; need to disallow=all before we can
use allow=
allow=ulaw			; Note: In user sections the order of
codecs
				; listed with allow= does NOT matter!
allow=alaw
allow=g723.1			; Asterisk only supports g723.1
pass-thru!
allow=g729			; Pass-thru only unless g729 license
obtained


;[xlite1]
;Turn off silence suppression in X-Lite ("Transmit
Silence"=YES)!
;Note that Xlite sends NAT keep-alive packets, so
qualify=yes is not needed
;type=friend
;username=xlite1
;callerid="Jane Smith" <5678>
;host=dynamic
;nat=yes                       ; X-Lite is behind a
NAT router
;canreinvite=no                ; Typically set to NO
if behind NAT
;disallow=all
;allow=gsm                     ; GSM consumes far less
bandwidth than ulaw
;allow=ulaw
;allow=alaw


;[snom]
;type=friend			; Friends place calls and receive calls
;context=from-sip		; Context for incoming calls from
this user
;secret=blah
;language=de			; Use German prompts for this user 
;host=dynamic			; This peer register with us
;dtmfmode=inband		; Choices are inband, rfc2833, or
info
;defaultip=192.168.0.59		; IP used until peer
registers
;username=snom			; Username to use in INVITE until
peer registers
;mailbox=1234,2345		; Mailboxes for message waiting
indicator
;restrictcid=yes		; To have the callerid restriced ->
sent as ANI
;disallow=all
;allow=ulaw                     ; dtmfmode=inband only
works with ulaw or alaw!
;mailbox=1234 at context,2345      ; Mailbox(-es) for
message waiting indicator


;[pingtel]
;type=friend
;username=pingtel
;secret=blah
;host=dynamic
;insecure=yes			; To match a peer based by IP address
only and not peer
;insecure=very			; To allow registered hosts to call
without re-authenticating
;qualify=1000			; Consider it down if it's 1 second to
reply
				; Helps with NAT session
				; qualify=yes uses default value
;callgroup=1,3-4		; We are in caller groups 1,3,4
;pickupgroup=1,3-5		; We can do call pick-p for call
group 1,3,4,5
;defaultip=192.168.0.60		; IP address to use if peer
has not registred

;[cisco1]
;type=friend
;username=cisco1
;secret=blah
;qualify=200			; Qualify peer is no more than 200ms
away
;nat=yes			; This phone may be natted
				; Send SIP and RTP to  IP address that packet is 
				; received from instead of trusting SIP headers 
;host=dynamic			; This device registers with us
;canreinvite=no			; Asterisk by default tries to
redirect the
				; RTP media stream (audio) to go directly from
				; the caller to the callee.  Some devices do not
				; support this (especially if one of them is 
				; behind a NAT).
;defaultip=192.168.0.4

;[cisco2]
;type=friend
;username=cisco2
;fromuser=markster		; Specify user to put in "from"
instead of callerid
;fromdomain=yourdomain.com	; Specify domain to put in
"from" instead of callerid
				; fromuser and fromdomain are used when Asterisk
				; places calls to this account.  It is not used
for
				; calls from this account.
;secret=blah
;host=dynamic
;defaultip=192.168.0.4
;amaflags=default		; Choices are default, omit,
billing, documentation
;accountcode=markster		; Users may be associated with
an accountcode to ease billing




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