Example Setup, Asterisk running on the same machine as siproxd (= NAT host).

I use a iptables rule to redirect all outgoing SIP traffix from Asterisk
to siproxd.

/etc/sysconfig/iptables:
------------------------
*nat
######################################################################
# NAT: redirect locally generated packets
:OUTPUT - [0:0]
#########################
#
# Asterisk Traffix via local siproxd. (must use DNAT to inbound IF! not REDIRECT)
-A OUTPUT -o ppp+ -p udp --sport 5061 -j DNAT  --to-destination 192.168.1.1:5060

COMMIT




/etc/asterisk/sip.conf:
-----------------------
[general]
context = default
allowoverlap = no  ; Disable overlap dialing support. (Default is yes)
bindport = 5061    ; use a different port than 5060, as that port will be
                   ; occupied by siproxd!
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

; g726 sounds very bad, useless!
; g722 is a dead end, no conversion from/to possible
; g729 sound like through a long metal tube
disallow = all
allow = gsm,ulaw,alaw,adpcm,speex,g729,g723
autoframing = yes

allowexternaldomains = yes
allowexternalinvites = yes
allowguest = yes
allowsubscribe = no
allowtransfer = yes
alwaysauthreject = no
autodomain = yes
callevents = no
compactheaders = no
dumphistory = no
g726nonstandard = no
ignoreregexpire = no
jbenable = no
jbforce = no
jblog = no
maxcallbitrate = 384
maxexpiry = 3600
minexpiry = 180
notifyringing = no
pedantic = no
promiscredir = no
recordhistory = no
relaxdtmf = no
rtcachefriends = no
rtsavesysname = no
rtupdate = no
sendrpid = yes
sipdebug = no
t1min = 100
progressinband = no
t38pt_udptl = no
trustrpid = no
usereqphone = no
videosupport = no
;
; the following is required when using siproxd with local DNAT rule
nat=never
externip=192.168.1.1
;
localnet = 192.168.0.0/16  ; my inbound network with local UAs
domain = 192.168.1.1       ; inbound IP of host running Asterisk and siproxd
domain = mynatfirewall     ; -"-
canreinvite = no

useragent = PBX            ; sipcall.ch (and others?) require UA string
                           ; to be different from "AsteriskPBX"

[authentication]
;---end---


/etc/asterisk/users.conf
------------------------
[general]
;
; Full name of a user
;
fullname = New User
userbase = 200
;
; Create voicemail mailbox and use use macro-stdexten
;
hasvoicemail = yes
;
; Set voicemail mailbox 6000 password to 1234
;
vmsecret = 1234
;
; Create SIP Peer
;
hassip = yes
hasiax = no
;
;
; Create manager entry
;
hasmanager = no
;
; Remaining options are not specific to users.conf entries but are general.
;
callwaiting = yes
threewaycalling = yes
callwaitingcallerid = yes
transfer = yes
canpark = yes
cancallforward = yes
callreturn = yes
callgroup = 1
pickupgroup = 1
host = dynamic
localextenlength = 3
allow_aliasextns = no
allow_an_extns = no
hasagent = no
hasdirectory = no

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Local SIP UAs
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
[201]
callwaiting = yes
cid_number = 201
context = local_sip
email = email@host.xx
fullname = Full Name
group = 
hasagent = yes
hasdirectory = yes
hasiax = no
hasmanager = no
hassip = yes
hasvoicemail = yes
host = dynamic
mailbox = 201
secret = <secret for AUTH>
threewaycalling = yes
zapchan = 
registeriax = no
registersip = yes
vmsecret = <secret for voicemail>

[202]
callwaiting = yes
cid_number = 202
context = local_sip
email = email@host.xx
fullname = Full Name
group = 
hasagent = yes
hasdirectory = yes
hasiax = no
hasmanager = no
hassip = yes
hasvoicemail = yes
host = dynamic
mailbox = 202
secret = <secret for AUTH>
threewaycalling = yes
zapchan = 
registeriax = no
registersip = yes
vmsecret = <secret for voicemail>


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; SIP Trunks
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; sipphone.com
[trunk_1]
disallow = all
allow = gsm,ulaw,alaw,adpcm,speex,g729,g723
callerid = 
contact = 1747669xxxx
context = DID_trunk_1
dialformat = ${EXTEN:1}
fromdomain = proxy01.sipphone.com
fromuser = 1747669xxxx
group = 
hasexten = no
hasiax = no
hassip = yes
host = proxy01.sipphone.com
insecure = very
port = 5060
provider = 
registeriax = no
registersip = yes
secret = <secret for AUTH>
trunkname = Custom - sipphone1341
trunkstyle = customvoip
username = 1747669xxxx

; sipcall.ch
[trunk_3]
disallow = all
allow = gsm,ulaw,alaw,adpcm,speex,g729,g723
callerid = 
contact = 4132511xxxx
context = DID_trunk_3
dialformat = ${EXTEN:1}
fromdomain = sip.backbone.ch
fromuser = 4132511xxxx
group = 
hasexten = no
hasiax = no
hassip = yes
host = sip.backbone.ch
insecure = very
port = 5060
provider = 
registeriax = no
registersip = yes
secret = <secret for AUTH>
trunkname = Custom - sipcall
trunkstyle = customvoip
username = 4132511xxxx

;---end---