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SIP Trunk with Cloud PBX without CUBE

Level 1
Level 1


we are configuring a SIP Trunk against a Cloud PBX without a CUBE (PoC purpose). The problem I have is that for this service SIP ALG in firewal should be disabled, so when call arrives, IP received is different than CUCM IP. If we enable SIP ALG all works fine except call transfer.


I'll try to solve it adding URI with natted IP address without succes.


Any ideas to solve the problem?



3 Replies 3

Anthony Holloway
Cisco Employee
Cisco Employee
I can't imagine what exact problems you have, but if you are NATing SIP without an ALG, then you'll likely need to implement SIP normalization scripts on your SIP Trunk in CUCM to manipulate the header and possibly SDP body.

Dennis Mink
VIP Alumni
VIP Alumni

What firewall are you using? Asa firepower. These are quite good when enabling sip inspection in conjunction with nattjng sip. Not sure about palo paltos

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What client did you use?
If it 3rd party, it can be troubles with Rerouting CSS on device configuration. Please check this field on phone configuration page.
If you wish to use 3rd-party for call transfer Rerouting CSS must have access to correct call routing.
May be you can share logs from CUCM for this call with us?
Be ready