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[SOLVED]DNS best practice?

There are two ways to configure DNS:

One way:
- Allowing DNS outgoing for your internal nameservers
- internal nameservers forwarding to ISP-DNS
- ASG pointing to internal nameservers 

Another way:
- ASG forwarding to ISP-nameservers
- "request routing" on ASG for internal domain pointing to internal nameservers
- internal nameservers forwarding to ASG
 
Which way do you use? And why? Which is "officially preferred"?
Both configurations seem working good for me, we run the first alternative on our cluster, the second in branch offices without internal dns (domain dns reachable via site2site-vpn).

Thanks for your ideas!
Thomas



BAlfson's DNS Best Practice's post has been moved to it's own highlighted thread here: https://community.sophos.com/utm-firewall/f/recommended-reads/122972/dns-best-practice
[edited by: FloSupport at 11:12 AM (GMT -7) on 18 Sep 2020]
  • Any thoughts on using root hints over forwarders for Domain Controllers?
  • Hi, James, and welcome to the User BB!

    Check out DNS Best Practice.

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • So is Request routing the same as Conditional Forwarders in Windows Server?

    Thanks?

    JK


    Yes it is the same.

    Managing several Sophos firewalls both at work and at some home locations, dedicated to continuously improve IT-security and feeling well helping others with their IT-security challenges.

  • So is Request routing the same as Conditional Forwarders in Windows Server?

    Thanks?

    JK

    JK

    CompKickers

  • I'm having an issue with DNS that I can't seem to figure out.  I would greatly appreciate any and all help!!

    Under DNS > Global > empty
    Forwarders > OpenDNS & Internal DNS (DC) & Use forwarders ISP(unchecked)
    Request Routing > mydomain.com > Internal DNS (DC) & .in-addr.arpa for each subnet > Internal DNS (DC)
    UTM is also joined to domain under SSO

    When I use DNS lookup from UTM I'm able to resolve IP to hostnames and vise versa, but reporting only resolves a few entries.  On my DNS server I have correct records and zones for forward and reverse.  

    Any ideas???

    Thanks,

    James
  • Good point, BD.  I was just thinking about avoiding .com.  Although there are still a lot of internal domains with .local, given the choice, something like .loc, .home or .office is better.  Check out the post and the Changelog. [;)]

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • My preference is to use .local so that you can use split DNS internally for .com.  If, for example, you were using Email Protection and sending Quarantine Reports, you would want mail.domain.com to resolve to the External IP if you were outside the office and to the Internal IP inside your LAN.

    The UTM joins domain.local correctly even though its hostname is .com.

    Cheers - Bob
    I've been looking at pfsense lately. The setup documentation recommends not to use .local:

    Do not use 'local' as a domain name. It will cause local hosts running mDNS (avahi, bonjour, etc.) to be unable to resolve local hosts not running mDNS.
    e.g. mycorp.com, home, office, private, etc.
  • My preference is to use .local so that you can use split DNS internally for .com.  If, for example, you were using Email Protection and sending Quarantine Reports, you would want mail.domain.com to resolve to the External IP if you were outside the office and to the Internal IP inside your LAN.

    The UTM joins domain.local correctly even though its hostname is .com.

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • Hi Bob,

    I have read your DNS best practics but this part was not clear to me.

    In your opinion what would you recommend for a network design using domainname.com or domainname.local internally. Provided that you own domainname.com

    To be clear I understand that the UTM will use UTMhostname.domainname.com that is a public resolvable FQDN.

    My question is about the internal network devices like server1.domainname.?
  • You should not disable recursion in virtually any environment where a UTM is used.

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA