[Serusers] Ser+RTPproxy+Asterisk
Alex Bligh
alex at alex.org.uk
Tue Jun 8 13:29:35 CEST 2004
A brief inspection suggests the config file is designed for a situation
where ser is outside the firewall (on "real IPs") and the UA is
inside the firewall.
It is getting confused at the start of route[1] because it sees the
next hop as inside the firewall (using a hueristic test based on IPs).
This is because it seems that ser itself is on RFC1918 space in you
configuration (from the alias line in your config), and the config
seems to be designed for a situation where asterisk and ser are
not in RFC1918 space.
If ser is the same side of the firewall as asterisk and the UA, you should
not need rtpproxy.
If ser and the UA are one side, and asterisk is the other, you are
probably better using the NAT tranversal stuff in asterisk.
If what you are trying to do is:
NAT1 NAT2
UA ----|-----SER-----|----Asterisk
or
NAT1 NAT2
UA-----|----SER, Asterisk ----|---- Internet
then the block at the top of route[1] is being triggered falsely,
and you are probably safe deleting it.
You will need to supply a network diagram for more help.
Alex
--On 08 June 2004 02:49 +0200 Sanjay Duggal <Sanjayd at Pressis.com> wrote:
>
> Hi All
>
> I`m new to this and like to learn how to set up the configure following
> Ser+RTPproxy+Asterisk
>
> Just to clarify the net settings
>
> My ser is on a public ip net and has a local address to.
> I will like to make a phone call from a sip phone which is
> behind NAT to a PSTN.
>
> When I try to call out I get
>
> "479", "We don't forward to private IP addresses"
>
>
> I don’t`know what i`m doing wrong
>
>
>
>
> Sending a copy of my ser.cfg
>
>
> alias=" mydomian.com "
> Alias="192.168.10.100" #ser
> Alias="192.168.10.120" #Asterisk
>
> 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"
> fifo_mode=0777
>
># ------------------ module loading ----------------------------------
>
># Uncomment this if you want to use SQL database
> loadmodule "/usr/local/lib/ser/modules/mysql.so"
>
> 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/textops.so"
>
># Uncomment this if you want digest authentication
># mysql.so must be loaded !
> loadmodule "/usr/local/lib/ser/modules/auth.so"
> loadmodule "/usr/local/lib/ser/modules/auth_db.so"
>
># !! Nathelper
> loadmodule "/usr/local/lib/ser/modules/nathelper.so"
>
># ----------------- setting module-specific parameters ---------------
>
># -- usrloc params --
>
> modparam("usrloc", "db_mode", 0)
>
># Uncomment this if you want to use SQL database
># for persistent storage and comment the previous line
> modparam("usrloc", "db_mode", 2)
>
># -- auth params --
># Uncomment if you are using auth module
>#
> modparam("auth_db", "calculate_ha1", yes)
>#
># If you set "calculate_ha1" parameter to yes (which true in this config),
># uncomment also the following parameter)
>#
> modparam("auth_db", "password_column", "password")
>
># -- rr params --
># add value to ;lr param to make some broken UAs happy
> modparam("rr", "enable_full_lr", 1)
>
>
># -- rr params --
># add value to ;lr param to make some broken UAs happy
> 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 -------------------
>
># main 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;
> };
>
> # !! Nathelper
> # 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
> if (nat_uac_test("3")) {
> # 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:")) {
> log("LOG: 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") {
> 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
> if
> (!method=="REGISTER") record_route();
>
> # subsequent messages withing a dialog should take the
> # path determined by record-routing
> if (loose_route()) {
> # mark routing logic in request
> append_hf("P-hint: rr-enforced\r\n");
> route(1);
> break;
> };
>
> if (uri=~"sip:0[0-9]*@mydomian.com"){
> rewritehostport("192.168.120.:5060");
> t_relay();
> #break;
>
> # forward(192.168.10.120,5060);
> # Where local asterisk is listening
> # break;
> }
>
># if (!uri==myself) {
> # mark routing logic in request
># append_hf("P-hint: outbound\r\n");
># route(1);
># 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)
> if (uri==myself) {
>
> if (method=="REGISTER") {
>
># Uncomment this if you want to use digest authentication
># if (!www_authorize("iptel.org", "subscriber")) {
># www_challenge("iptel.org", "0");
># break;
># };
> save("location");
> break;
> };
> lookup("aliases");
> if (!uri==myself) {
> append_hf("P-hint: outbound alias\r\n");
> route(1);
> break;
> # native SIP destinations are handled using our USRLOC DB
> if (!lookup("location")) {
> sl_send_reply("404", "Not Found");
> break;
> };
> };
> append_hf("P-hint: usrloc applied\r\n");
> route(1);
> }
> route[1]
> {
> # !! Nathelper
> if (uri=~"[@:](192\.168\.|10\.|172\.(1[6-9]|2[0-9]|3[0-1])\.)" &&
> !search("Route:")){
> sl_send_reply("479", "We don't forward to private IP
> addresses");
> break;
> };
>
> # if client or server know to be behind a NAT, enable relay
> record_route();
> if (isflagset(6)) {
> fix_nated_sdp("1");
> force_rtp_proxy();
> t_on_reply("1");
> }
> #if (isflagset(6)) {
> # force_rtp_proxy();
> #};
>
> # NAT processing of replies; apply to all transactions (for
> example, # re-INVITEs from public to private UA are hard to
> identify as # NATed at the moment of request processing); look at
> replies t_on_reply("1");
>
> # send it out now; use stateful forwarding as it works reliably
> # even for UDP2TCP
> if (!t_relay()) {
> sl_reply_error();
> };
> }
>
># !! Nathelper
> onreply_route[1] {
> # NATed transaction ?
> if (isflagset(6) && status =~ "(183)|2[0-9][0-9]") {
> fix_nated_contact();
> fix_nated_sdp("1");
> force_rtp_proxy();
> # otherwise, is it a transaction behind a NAT and we did not
> # know at time of request processing ? (RFC1918 contacts)
>
> } else if (nat_uac_test("1")) {
> fix_nated_contact();
> };
> }
>
>
>
> regards
>
> Sanjay
>
>
> ---
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>
Alex
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