Z3 - change routes

FlyingDutchman
Conversationalist

Z3 - change routes

Hi,

 

I have a challenge with the following setup:

 

  • Z3 to MX250 - default DNS server = corporate
  • The default route on the S2S VPN settings for the hub is disabled (=local internet breakout on the Z3)
  • Telefon service for Cisco Webex connects to voipserver.company.com
  • Corporate DNS server has an internal IP for voipserver.company.com that routes the VoIP-traffic internally via MPLS to the VoIP-provider
  • Public DNS also has an IP for voipserver.company.com that points to the public Expressway of the VoIP-provider for external clients

How do I setup the Z3/ network so that all Z3's connect to the public instead of the corporate IP of the VoIP-Provider?

 

Thanks in advance!

 

6 REPLIES 6
UCcert
Kind of a big deal

Re: Z3 - change routes

Are you over thinking this?  Can’t you create a new vlan and dhcp pool that assigns a public dns IP address?

Darren O'Connor | uccert.co.uk
https://www.linkedin.com/in/darrenoconnor/

I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.
cmr
Kind of a big deal
Kind of a big deal

Re: Z3 - change routes

@UCcert I think @FlyingDutchman wants to use their internal DNS for internal servers, but not for the VoIP server.  However they have a DNS entry for the VoIP server on their internal servers that points to a suboptimal IP address.

 

Therefore the only options I can think of are:

 

  • Remove internal entry for VoIP server and use public expressway for all connections
  • Allow remote users to connect to VoIP server via existing MPLS route
  • Maintain a second internal DNS server with only a subset of internal entries (not including the VoIP server) and point the VPN clients to that
  • Somehow filter the responses the DNS server gives, so only internal hosts get the private VoIP server entry, but VPN hosts get the public entry <--- can this be done?

Unless of course I am overthinking this!

UCcert
Kind of a big deal

Re: Z3 - change routes

@cmr  😆

 

I think you’re right.

Darren O'Connor | uccert.co.uk
https://www.linkedin.com/in/darrenoconnor/

I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.
KarstenI
Head in the Cloud

Re: Z3 - change routes

The forth option that @cmr mentioned would work well, this feature is named "DNS views" and is supported in BIND, but sadly not on Windows Server DNS.

So the best long-term solution would be not to use the same domain for internal and external resources. The internal resources should be better migrated to a different domain or a subdomain of company.com.

 

EDIT: Wait ... just the moment I pressed "Post" I remembered there was a new feature that does exactly what DNS views in BIND are doing, the DNS policies:

https://docs.microsoft.com/en-us/windows-server/networking/dns/deploy/dns-policies-overview

These can be used for this, but are not that easy to configure.

FlyingDutchman
Conversationalist

Re: Z3 - change routes

Hi @KarstenI & @cmr ,

this is certainly an interesting approach that I will gonna test. 
I'll get back as soon as possible, thanks!

PhilipDAth
Kind of a big deal

Re: Z3 - change routes

You could configure Windows 10 NRPT - DNS resolution policy.

 

Configure the policy to send voipserver.company.com to public DNS servers (like 8.8.8.8) and let everything use the default configured DNS servers.

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