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How do you make skype connect work with UC520 8.04 software pack?


I have a UC520 that has been defaulted and the wizard bypassed the telephony wizard. It is 100% default config at this point.

I referred to this document: Skype4sip-uc500.pdf (1.5 MB) in setting it up and followed the instructions related to sip trunks.

I setup a sip trunk in CCA 2.2.5 using for the servers, for the domain, for dns, and my account username and password for digest. I also added user credentials using my same username and password to attempt to register a channel.

I had already ordered skype connect and purchased a channel.

I get no sip registration and the ccd debug tool only shows messages for REGISTER.

I am trying to stay 100% CCA and as skpe is certified I shouldnt have to do any CLI at all.

I am not sure what else to do or is there somethign else I need to do  in CCA that was not in that document in order to allow the sip trunks  to register.

Please give me a  hand I really need to make this work.



12 Replies 12


I did some digging and I am getting a dns error.

... sip/error/ _send_dns_fail: DNS Query for failed

....sip/error/act_register_dns_resolved: DNS Query failed for query_type:1

I used for the dns entry on the skype config screen. I can ping and get resolution from the router, so why does dns fail?

How does sip run dns for the sip server?

Please help.



Louis Gencarelli

Greetings Johnny --  seems that Skype may have made some changes on their end which do not map directly to the template used in CCA 2.2.5 --

I've revised the Skype4sip-uc500.pdf (updated to v1.2 attached below)  

You'll note the biggest changes regarding inbound & outbound dialing plans.

Hope this helps.


The link to the xml file does not exist in section 3.

I tried using CCA 2.2.5 with a UC540 and get the same result using the settings provided by Skype.

1. no registration

2. no dns resolution for some reason. I can ping but in the sip registration is shows that fails the dns query.

What dns server should I use? I tried on the skpe setup in sip trunks and uses as the domain and it failed.

Now two differnt routers will not work at all even with the firewall turned off.

Anyone have any ideas?

Louis Gencarelli

Hi Johnny -

If you're using CCA 2.2.5 then you will automatically have the "Skype for SIP" template available in the drop down list when you go to Configure --> Telephony --> Trunks --> Sip Trunks:  Service Provider drop down.   So you will not need to download it.   The XML file was created for earlier versions of CCA so that users could install the template manually.   

Re: DNS – should work – here’s the output I get when I do an nslookup from a dos prompt




Non-authoritative answer:




Be sure to reference all the preliminary steps required on the Skype side first at:

To confirm whether or not Skype see’s your registration attempts:

Make sure you’re logged into Skype Manager at à

Check the Authentication Details page under the Skype Connect Profile to determine if the UC500 has registered successfully with skype using Registration (username/password) option vs IP Authentication  (see picture)

Similarly, you can confirm successful registration in CCA via the Monitor drawer --> Telephony -->Sip Trunk Status

  Check the various windows to see whether:  Sip Serivce is UP


do a "show sip-ua register status" from IOS Exec Commands (or cli)  to confirm:

Line          peer           expires(sec)  registered   P-Associated-URI
============  =============  ============  ===========  ================
9905XXXXXXXX  -1               45            yes      

Finally, although rare, you may want to check with your ISP as it could be possible that your Internet Service Provider filters SIP (port 5060)…    here’s an article I stumbled across:

Good Luck!

I thank you for your help so far. Everytime I move forward however, I take a step back.

I appreciate the info on your last post and I have followed all of those procedures prior to posting this discussion. I did not however process incoming dialplan as I do not plan to recieve calls here, only make calls.

When I setup the system for XO skype we didnt need the creditials to make outbound calls, only to bring the calls inbound. As long as the digest authentication was in place everything worked. They also used the same authenication for digest and the credentials so you would see two registrations at times.

I am not sure how to tell if the port is blocked outgoing. I know I had the firewall turned off on the UC540 but the tools said that the port was blocked.Do you know of a way to test for an outbound block.

So back to tech. Even though the router could resolve and ping, and my pc can do an nslookup for, the sip error still stated that it couldnt resolve I think it has something to do with the ip domain name somehow since when I manually removed that command, the resolution worked.The new problem is that as this was a voice ignite program demo, we have intercom created and for some reason the system was using one of the intercom credentials to register with skype rather than my skype account I used for digest and the credentials. I used the ccsip debugs to find this out.

How is that possible? When I do a show sip reg stat it shows not only my skype account but all the intercom accounts.

Now I am really stuck but I moved forward? hahah I dont know. Kill me please.

I've read that the safest way to change from one sip profile (xo) to another (skype) via CCA, you need to first set the profile to 'none' hit apply and make sure all the old settings are cleared out.   then select the new sip trunk provider and configure that...

if your system somehow has 2 sets of sip profiles combined,  then I'd guess the best/fastest bet is to factory reset and start from scratch...  you can do this from the maintenance drawer -->  restart/reset -->  check the reset to factory checkbox along with restart of the UC5xx.

as far as port scanners go -- I have no preference -- just google 'port scanner'...  there are a bunch of free and/or cheap ones available...

here's a web based one:

hope it helps.

I am sorry, I was only referencing XO as something I had done in the past.

I am only trying to make this work with Skype and it is the only sip provider I have attempted to configure on this device.

My problem now is that the system is trying to register with my intercom credentials rather than my skype credential.

So it says (scrubbed):

From: <>*DB205@myipaddress>;tag=51925a83-3dc

instead of :

From: <>9905xxxxxxxxxx@myipaddress>;tag=51925a83-3dc

Any idea what to look at for that?

SUCCESS! (registration anyway)

It wasnt me after all. I had to delete all types of intercoms from the system and which left only my Skype username. Then it registered.

Why did I have to delete my intercoms to make a sip registration work? This is a 100% CCA setup router with the exception of removing the ip domain name (which fixed one problem). Perhaps someone can update the XML to remove the requirement for the ip domain name.

I am still unable to make a call but I am working on it.

not sure re:intercoms...  but great news on the successful registration...

If you're only interested in outbound calls,  just be sure that when you setup Configure--> Telephony--> Dial Plan --> Outbound:

you use the skype user id (the 90051000xxxx number) for the Caller ID Main PSTN Number field...

Yes I have it the same but after an hour with skype tech they say the calls are never getting to them.

I keep getting a 404 error and on the handset it says unknown number. I am not sure what else to check on this new problem.

Any ideas?


I'm struggling to get this working and would really appreciate any help, the bit I don't understand in the PDF is where it says "Enter DID range start / end as the Skype for SIP numbers (9905…….)"

Where do I get these DID numbers from? 



Those numbers come with a Skype Connect account.  Check out the first Skype video in this link and you'll understand what i am referring to.

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