The growing importance of DNS in your CUCM configs

Hi Guys!

It used to be that DNS was an afterthought for most CUCM deployments, many engineers advocated at one point or another just using an IP address rather than dealing with the system team who could either be extremely cooperative or extremely slow.

Those days are GONE, my friends. 

Every bit of UC software you use should be properly configured with DNS.

 Infact, anywhere you CAN use DNS, you should be using it.

The main driver for this is definitely Jabber, I can't count the number of things that can go wrong with Jabber if you do not have your DNS configured correctly.

If you absolutely must get a system up very rapidly and the sysadmin team have been very slow to get there side finished, you can use a router as a temporary DNS server:

The config for this is shown below:

conf t
 ip domain-name
ip  dns server
ip name-server 8.8.8.8 4.4.2.2

ip host _cisco-uds._tcp.ccierants.com srv 0 10 8443 cucm01.ccierants.com
ip host cucm01 192.168.1.10
ip host unity 192.168.1.20

ip host imp 192.168.1.30
ip host _cuplogin._tcp.ccierants.com srv 0 10 8443 imp.ccierants.com



As you can see from the example above, you can use the host command to specify manual DNS entries, you can even do SRV records etc, the only records i can't seem to see are CNAME records, but for our purposes this does not matter.

You can then point your UC servers to this router as there DNS server as a temporary workaround while you wait for the system administration team.

27 comments:

  1. Just bear in mind that changing your DNS settings will change your licensing MAC.

    ReplyDelete
  2. Hi Peter,

    I just found your blog while trying to troubleshoot an issue with a new user and their EM Home-cluster problems on a single-cluster site. I jsut want to say thanks for that post! I'm doing my first build of a CUCM, CUC and IMP cluster and was wondering why you find it best to keep the DNS entries? What are the benefits here over going straight IP? My colleague who has done these for many years stated specifically to alter the DNS entries for the various enterprise services on CUCM so I'm very interested in your methodology here.

    Thanks very much again,

    Dan

    ReplyDelete
  3. Superb i really enjoyed very much with this article here. Really its a amazing article i had ever read. I hope it will help a lot for all. Thank you so much for this amazing posts and please keep update like this excellent article.

    Digital Marketing Training

    ReplyDelete
  4. Great blog..You have clearly explained about the concept of DNS..Step by step explanation is too good to understand..Its very useful for me to understand..Keep on sharing..
    Java Training in Chennai

    ReplyDelete
  5. Hi Peter

    I wrote a longer post, but seems to have been lost...

    On a recent deployment, I was fortunate to have an extended engagement with the Cisco BU dial plan team when completing a mult-cluster design. Even in 11.x, CUCM does not support DNS caching. So for SIP Trunking in CUCM, multiple dotted IP Addresses are probably still the way to go! Only time this changes will obviously be with a secure connection where certificates come into play.

    That being said, I pretty much use DNS SRVs on all CUBE dial-peers, IM and Presence etc as far as I can. Don't think I've deployed a cluster without DNS for ages.

    CNAMEs also are great, and as best practice with CVD. Great for end users with a simple "www" address pointing to the pub.

    ReplyDelete
  6. Thanks for the excellent article Peter. Just to clarify are you saying in CUCM under System/Cisco Unified CM the best practice is to leave that as a hostname and not change it to the IP address? What about the URLs in the Enterprise Parameters? Also leave that as hostnames? I have always configured DNS on CUCM (DNS name and DNS server IP) but I remove the reliance on DNS from the Cisco Unified CM and the Enterprise Parameters. Will this cause an issue with Jabber?

    Thanks,

    Kevin

    ReplyDelete
  7. Very nice post here and thanks for it .I always like and such a super contents of these post.Excellent and very cool idea and great content of different kinds of the valuable information's.
    Selenium Training in Chennai | Selenium Training in Bangalore | Selenium Training in Pune | Selenium online Training

    ReplyDelete
  8. This is most informative and also this post most user friendly and super navigation to all posts... Thank you so much for giving this information to me.. 
    Java training in Bangalore | Java training institute in Bangalore | Java course in Bangalore

    Java interview questions and answers

    Core Java interview questions and answers

    ReplyDelete
  9. Useful information.I am actual blessed to read this article.thanks for giving us this advantageous information.I acknowledge this post.and I would like bookmark this post.Thanks
    online Python training
    python training in chennai

    ReplyDelete
  10. Great post! I am actually getting ready to across this information, It’s very helpful for this blog.Also great with all of the valuable information you have Keep up the good work you are doing well.
    angularjs Training in bangalore

    angularjs Training in btm

    angularjs Training in electronic-city

    angularjs online Training

    angularjs Training in marathahalli

    angularjs interview questions and answers

    ReplyDelete
  11. Very nice post here thanks for it .I always like and such a super contents of these post.Excellent and very cool idea and great content of different kinds of the valuable information's.
    machine learning course in Chennai
    machine learning training center in Chennai
    machine learning with python course in Chennai

    ReplyDelete
  12. When attempting for a tough certification like 1Z0-987 exam, the quality of the study material can never be compromised.
    I downloaded 1Z0-987 real exam dumps after a satisfied study and investigation about the reliability of this stuff.
    Now after getting passed in my Oracle Cost Management Cloud 2017 Implementation Essentials 1Z0-987 I have come to know the actual value of 1Z0-987 braindumps. I suggest the same for all IT candidates of all type of IT certifications exams preparation material.

    ReplyDelete
  13. Wonderful thanks for sharing an amazing idea. keep it...

    Learn Best PEGA Training in Bangalore from Experts. Softgen Infotech offers the Best PegaTraining in Bangalore.100% Placement Assistance, Live Classroom Sessions, Only Technical Profiles, 24x7 Lab Infrastructure Support.

    ReplyDelete
  14. Such a great information for blogger i am a professional blogger thanks…

    Looking for Best Training Institute in Bangalore , India. Softgen Infotech is the best one to offers 85+ computer training courses including IT Software Course in Bangalore , India. Also, it provides placement assistance service in Bangalore for IT.

    ReplyDelete
  15. Thank you for your post. This is excellent information. It is amazing and wonderful to visit your site.Prathima Infotech training center bangalore

    ReplyDelete
  16. Nice Blog
    "Pressure Vessel Design Course is one of the courses offered by Sanjary Academy in Hyderabad. We have offer professional
    Engineering Course like Piping Design Course,QA / QC Course,document Controller course,pressure Vessel Design Course,
    Welding Inspector Course, Quality Management Course, #Safety officer course."
    Piping Design Course
    Piping Design Course in India­
    Piping Design Course in Hyderabad
    Welding Inspector Course
    Quality Management Course
    Quality Management Course in india
    Safety officer course

    ReplyDelete
  17. Comprehensive National Football League news, scores, standings, fantasy games, rumors, and more.
    Saints Game
    Seattle Seahawks Football
    Minnesota Vikings Game
    Browns Football
    Baltimore Ravens Game

    ReplyDelete

Popular old posts.