[Serusers] Loose routing question

[reticent]

Currently (in rel_0_9_) the "loose_route()" function will NOT match a
message unless SER has some stateful information regarding that
transaction in memory (my assumption has been that the information is
created when the "record_route()" or "record_route_preset()" functions
are used and is referenced by "loose_route()" according to the "tag=..."
header field inside the "Route:" header), so simply adding a "Route:
..." header into the sip message will not be loose_routed.



Michael Ulitskiy wrote:

>Hello,
>
>I'm trying to comprehend loose routing concept and I have
>a question that concerns me.
>As far as I understand loose routing says that if there're Route
>headers in a message it should be forwarded according to the URIs
>set in Route headers. 
>I thought that this is true only within a dialog, but RFC3261 (part 16.6) says:
>"Requests establishing a dialog may contain a preloaded Route header field."
>Also SER manual says: " the failure not to include loose routing in your scripts 
>may lead to infinite loops. Make sure that you include the following script 
>fragment immediately after request sanity checks" and provide the following
>piece of code:
>if (loose_route()) {
>        t_relay();
>        break;
>};
>
>which as far as I understand unconditionally forwards message if Route header
>is present.
>So I'm wondering what about security? If I follow this guidelines how I would
>shield my PSTN gateway if anyone can construct message and 
>pre-load it with URI of my gateway and all my proxies must honor it.
>For example I have a PSTN gateway on ip address 10.1.1.5 and proxy
>on 10.1.1.10 that supposed to interface outside world.
>So I guess if someone construct a message like this:
>
>INVITE sip:12345 at somewhere.com SIP/2.0
>...
>Route: <sip:12345 at 10.1.1.5;lr>
>
>my proxy will forward it to PSTN gateway and it will make outbound call.
>
>Is this true? Please enlighten me on this.
>Thank you,
>
>Michael
>
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