[SR-Users] loose_route security

Juha Heinanen jh at tutpro.com
Sun Apr 17 18:16:37 CEST 2011

Iñaki Baz Castillo writes:

> I've never seen a PSTN gw properly handling a REFER, neither I think a
> PSTN gw should handle it (but a B2BUA/PBX) between the UA and the PSTN
> gw(s).

i don't see any problem if gw charges the call based on referred-by that
proxy has verified.  i think that even cisco ios gws with rather current
software can do that.

> Honestly I can imagine how a PSTN gw is supposed to assert the value
> of "Referred-By". Perhaps it just allows the REFER if it contains a
> Referred-By matching the From URI header?

gw does not assert the refer.  it is the proxy that does that.  gw
simply generates a call to pstn and places the number in referred-by
header to the charged party field of isdn or isup message.  exactly the
same as it does with diversion header, which has worked fine forever.

-- juha

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