[OpenSER-Devel] Cisco x-route-tag

[Klaus Darilion]

Daniel-Constantin Mierla schrieb:
> On 06/25/08 12:33, Klaus Darilion wrote:
>>
>>
>> Daniel-Constantin Mierla schrieb:
>>> Hello,
>>>
>>> On 06/18/08 06:11, Davey Goode wrote:
>>>> Hi All,
>>>>
>>>> Traditionally for outbound routing to the PTSN world via a cisco 
>>>> voice gateway we use HOC's or prefixes,  has anyone ever looked at 
>>>> incorporating the x-route-tag feature to replace the HOC/ prefix in 
>>>> openser ???
>>>>
>>>> In NZ we have a local code shop that has written a SIP proxy, they 
>>>> have incorporated it into their proxy and it works great!  it would 
>>>> be a really nice feature.
>>>>
>>>> I would be more than happy to contribute $ if someone wanted to 
>>>> write it.
>>>>
>>>> see
>>>>
>>>>
>>>>       
>>>> http://www.cisco.com/en/US/docs/ios/12_2t/12_2t11/feature/guide/ftgwrepg.html#wp1217685 
>>>>
>>>>
>>> did I understand correct that this will be solved by the possibility 
>>> of adding a custom parameter to the Via header going to be inserted 
>>> by the proxy itself?
>>
>> If I understand it right: yes
>>
>> This is IMO a dangerous feature. The docs says that if the topmost via 
>> header does not have such a tag it will search for the tags in the the 
>> other via headers. Thus, for example, if the users SIP client adds the 
>> parameter and the proxy just forwards the request (with adding a 
>> parameter itself and without screening existing via parameters) the 
>> client can enforce a certain trunk.
> Sounds like this. Perhaps the entity dealing with it, must have a second 
> layer of trust policies.
> 
> Now, do you find dangerous the possibility to add custom parameters to 
> Via headers or just this specific feature?

Just this specific feature, as it also accepts the via parameters from 
any via header. Thus, adding a function to add arbitrary via params can 
IMO be useful. I think reading the params is already possible using PVs 
and translations.

regards
klaus