[Serusers] Help needed : SER / PSTN / NAT
Klaus Darilion
klaus.mailinglists at pernau.at
Wed Mar 17 17:32:17 CET 2004
olivier at siteboulevard.com wrote:
> OK, thanks.
>
> On the following conf (in fact, the NAT example), where should i put the
> rewritehost and forward function to my CISCO ??
In front of the lookup("alias") I would check if the username is
numerical, then I would format it (according to the local dial plan) to
an E.164 number. After that I would do an ENUM lookup.
If after the ENUM lookup the request-URI is still an E.164 number, I
would rewrite the host.
Otherwise do the lookup-alias and lookup location.
In but cases, the message will be forwarded by the t_relay at the end of
your script.
Klaus
>
> #
> # $Id: nathelper.cfg,v 1.1.2.1 2003/11/24 14:47:18 janakj Exp $
> #
> # simple quick-start config script including nathelper support
>
> # This default script includes nathelper support. To make it work
> # you will also have to install Maxim's RTP proxy. The proxy is enforced
> # if one of the parties is behind a NAT.
> #
> # If you have an endpoing in the public internet which is known to
> # support symmetric RTP (Cisco PSTN gateway or voicemail, for example),
> # then you don't have to force RTP proxy. If you don't want to enforce
> # RTP proxy for some destinations than simply use t_relay() instead of
> # route(1)
> #
> # Sections marked with !! Nathelper contain modifications for nathelper
> #
> # NOTE !! This config is EXPERIMENTAL !
> #
> # ----------- global configuration parameters ------------------------
>
> debug=7 # debug level (cmd line: -dddddddddd)
> fork=yes
> log_stderror=yes # (cmd line: -E)
>
> /* Uncomment these lines to enter debugging mode
> 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"
>
> # ------------------ module loading ----------------------------------
>
> # Uncomment this if you want to use SQL database
> #loadmodule "/usr/local/lib/ser/modules/mysql.so"
>
> loadmodule "/usr/lib/ser/modules/sl.so"
> loadmodule "/usr/lib/ser/modules/tm.so"
> loadmodule "/usr/lib/ser/modules/rr.so"
> loadmodule "/usr/lib/ser/modules/maxfwd.so"
> loadmodule "/usr/lib/ser/modules/usrloc.so"
> loadmodule "/usr/lib/ser/modules/registrar.so"
> loadmodule "/usr/lib/ser/modules/textops.so"
>
> # Uncomment this if you want digest authentication
> # mysql.so must be loaded !
> #loadmodule "/usr/lib/ser/modules/auth.so"
> #loadmodule "/usr/lib/ser/modules/auth_db.so"
>
> # !! Nathelper
> loadmodule "/usr/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)
>
> # !! 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
> # use different transport protocol
> 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==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
> 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();
> force_rtp_proxy();
> # otherwise, is it a transaction behind a NAT and we did not
> # know at time of request processing ? (RFC1918 contacts)
> } else {
> fix_nated_contact();
> };
> }
>
>
>
>
>>
>>olivier at siteboulevard.com wrote:
>>
>>>Hi,
>>>
>>>After some testing on the latest release, i have some problem doing the
>>>following on LINUX :
>>>
>>
>>latest? du you mean unstable or latest stable?
>>
>>
>>>Scenario :
>>>- SIP Phones behind a NAT
>>>- SER server under linux with rtpproxy launched
>>>- a 3660 cisco gateway with PSTN connectivity enabled.
>>>
>>>When i call with SIP phone a PSTN number, everything is OK BUT no sound
>>>anywhere.
>>>
>>
>>Use ethereal to verfiy that the SDP in the INVITE and 200 OK (or 183
>>Early Media) are rewritten by nathelper&rtpproxy to point to the IP:port
>>of the rtpproxy. If this is correct, you should see RTP streams to
>>rtpproxy (which should be forwarded to the GW and the NAT box)
>>
>>
>>>I could not find a sample ser.cfg script that reflect this scenario. Could
>>
>>>someone send me this scenario ?
>>
>>this is like any other scenario with a client behind NAT and one client
>>with public IP.
>>
>>
>>>Maybe i missunderstood some things. In particular, do i need to launch two
>>
>>>instances of ser (one for outbound proxy, another for request. If yes, how
>>
>>to
>>
>>>do that)
>>
>>You don't need two instances.
>>
>>Klaus
>>
>>
>
>
>
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