Use Case 2: ISP Tenant Uses DNS Proxy to Handle DNS Resolution for
Security Policies, Reporting, and Services within its Virtual System
In this use case, multiple tenants (ISP subscribers)
are defined on the firewall and each tenant is allocated a separate
virtual system (vsys) and virtual router in order to segment its
services and administrative domains. The following figure illustrates
several virtual systems within a firewall.
Each tenant
has its own server profiles for Security policy rules, reporting,
and management services (such as email, Kerberos, SNMP, syslog,
and more) defined in its own networks.
For the DNS resolutions
initiated by these services, each virtual system is configured with
its own DNS Proxy Object to
allow each tenant to customize how DNS resolution is handled within
its virtual system. Any service with a Location will
use the DNS Proxy object configured for the virtual system to determine
the primary (or secondary) DNS server to resolve FQDNs, as illustrated
in the following figure.
For each virtual system, specify the DNS Proxy
to use.
Select DeviceVirtual Systems and Add the ID of
the virtual system (range is 1-255), and an optional Name,
in this example, Corp1 Corporation.
On the General tab, choose
a DNS Proxy or create a new one. In this
example, Corp1 DNS Proxy is selected as the proxy for Corp1 Corporation’s
virtual system.
For Interfaces, click Add.
In this example, Ethernet1/20 is dedicated to this tenant.
For Virtual Routers, click Add.
A virtual router named Corp1 VR is assigned to the virtual system
in order to separate routing functions.
Click OK.
Configure a DNS Proxy and a server profile to support
DNS resolution for a virtual system.
Select NetworkDNS Proxy and click Add.
Click Enable and enter a Name for
the DNS Proxy.
For Location, select the virtual
system of the tenant, in this example, Corp1 Corporation (vsys6).
(You could choose the Shared DNS Proxy resource
instead.)
For Server Profile, choose
or create a profile to customize DNS servers to use for DNS resolutions
for this tenant’s security policy, reporting, and server profile
services.
If the profile is not already configured, in the Server Profile field,
click DNS Server Profile to Configure a DNS Server Profile.
The
DNS server profile identifies the IP addresses of the primary and secondary
DNS server to use for management DNS resolutions for this virtual system.
Also for this server profile, optionally configure
a Service Route IPv4 and/or a Service
Route IPv6 to instruct the firewall which Source
Interface to use in its DNS requests. If that interface
has more than one IP address, configure the Source Address also.
Select the Advanced tab. Ensure
that Cache is enabled and Cache
EDNS Responses is enabled (both are enabled by default).
This is required if the DNS proxy object is used under DeviceVirtual SystemsvsysGeneralDNS Proxy.
Click OK.
Click OK and Commit.
Optional advanced features such as split
DNS can be configured using DNS Proxy Rules.
A separate DNS server profile can be used to redirect DNS resolutions
matching the Domain Name in a DNS
Proxy Rule to another set of DNS servers, if required.
Use Case 3 illustrates split DNS.
If you use two separate
DNS server profiles in the same DNS Proxy object, one for the DNS
Proxy and one for the DNS proxy rule, the following behaviors occur:
If a service route is defined in the DNS server profile used by
the DNS Proxy, it takes precedence and is used.
If a service route is defined in the DNS server profile used
in the DNS proxy rules, it is not used. If the service route differs
from the one defined in the DNS server profile used by the DNS Proxy,
the following warning message is displayed during the Commit process:
Warning: The DNS service route defined in the DNS proxy object is different from the DNS proxy rule’s service route. Using the DNS proxy object’s service route.
If no service route is defined in any DNS server profile,
the global service route is used if needed.