Guide to ISR G2 Configuration

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Updated:October 28, 2025
Document ID:225309

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    Introduction

    This document describes how to configure Cisco Integrated Services Router (ISR) G2.

    Background Information

    As the administrator of a ISR G2, you are able to use the DNS IP addresses of 208.67.222.222 and 208.67.220.220 of the global network. The service offers you visibility into all internet traffic originating from your ISR and results in a faster internet experience for your users.

    note-icon

    Note: This guide is for the ISR G2, not the ISR 4K series. See Integration for ISR 4K and ISR 1100 – Security Configuration Guide if you use an ISR 4K.

    Configure

    The next table outlines the differences between the the ISR G2 and the ISR 4K and their available packages.

    Feature

    ISR 4K

    ISR G2

    Built-in Connector

    Yes

    No

    DNS Layer Protection

    Yes

    Yes

    Intelligent Proxy

    Yes

    Yes

    SSL Decryption

    Yes

    Yes

    DNSCrypt-capable

    Yes

    No

    Policy Per Interface

    Yes

    No

    Transparent DNS Proxy

    Yes

    No

    DHCP/Endpoint DNS changes required

    No

    Yes

    Client IP Reporting

    Yes (requires Cisco IOS® XE version 16.6.1 or later)

    No

    Dynamic Public IP Address Support

    Automatic

    Via Dynamic DNS

    Umbrella Branch Package available

    Yes

    No 

    Other Umbrella Packages available

    Professional, Insights, Platform

    Professional, Insights, Platform

    Our DNS servers can be used as the name servers on your ISR G2. Example:

    hostname(config)# ip name-server 208.67.222.222 208.67.220.220
    hostname(config)# ip domain lookup
    note-icon

    Note: If your ISR G2 needs to resolve internal DNS then it must use internal DNS servers. In this scenario, the internal DNS servers are configured to use Umbrella as their DNS forwarders.

    You can also use the DNS servers for your ISR G2 DHCP server. As a result, the devices that receive addressing from your ISR G2 will also be protected. For example:

    hostname(config)# ip dhcp pool <pool_number>
    hostname(dhcp-config)# dns server 208.67.222.222 208.67.220.220

    Verify

    Once you have configured your ISR G2, see What are the Umbrella Test Destinations? in order to verify that Umbrella is working.

    Troubleshoot

    There is currently no specific troubleshooting information available for this configuration.

    Revision History

    Revision Publish Date Comments
    1.0
    30-Oct-2025
    Initial Release
    TAC Authored

    Contributed by Cisco Engineers

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