Verify DNS SRV records for Office 365

After adding the Office 365 SRV records in the external DNS, we like to verify the DNS SRV records. There are many ways to check the DNS SRV records. We will focus on how to check the DNS SRV records for Office 365 from a Windows machine and a website.

Information DNS SRV records for Office 365

There are two SRV records that we need to check in DNS:

• _sipfederationtls._tcp
• _sip._tls

It can take time before it actually will resolve. Don’t do a check immediately after you added the SRV record to your external DNS. It will most likely not yet got resolved.

Verify DNS SRV records from Windows

Let’s verify the SRV records for Office 365. In this example, we are going to verify the SRV records against the domain klm.com. Change the domain to yours. Start Command Prompt on your Windows machine.

C:\>nslookup
> set type=any
> set verbose
> _sipfederationtls._tcp.klm.com

Non-authoritative answer:
_sipfederationtls._tcp.klm.com  SRV service location:
          priority       = 100
          weight         = 1
          port           = 5061
          svr hostname   = sipfed.online.lync.com

> _sip._tls.klm.com

Non-authoritative answer:
_sip._tls.klm.com       SRV service location:
          priority       = 100
          weight         = 1
          port           = 443
          svr hostname   = sipdir.online.lync.com

The results are good. Both of the SRV records are added to DNS, and we can verify it. Now that we did an SRV lookup with Windows, we like to do that with a DNS lookup website.

Verify DNS SRV records from a website

Open your browser and go to the website mxtoolbox.com. Make sure that it’s showing DNS Lookup SRV at the top. Fill in the domain name _sipfederationtls._tcp.klm.com and click on the SRV Lookup button. Change klm.com to your domain.

The results will show that the SRV is added to DNS.

Do the same with _sip._tls. Fill in _sip._tls.klm.com and do an SRV Lookup.

Will you check the SRV records with Windows or with the website mxtoolbox.com? Both will work.

Read more: Exchange namespace design and planning »

Conclusion

To sum it up, you learned how to check the DNS SRV records for Office 365. Not only did you learn how to check the DNS SRV records with Windows, but also with a DNS lookup website.

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