SonicOS 7 Match Objects
- SonicOS 7
- Zones
- How Zones Work
- Predefined Zones
- Security Types
- Allow Interface Trust
- Enabling SonicWall Security Services on Zones
- Effect of Wireless and Non-Wireless Controller Modes
- Match Objects > Zones
- The Zone Settings Table
- Adding a New Zone
- Configuring a Zone for Guest Access
- Configuring a Zone for Open Authentication and Social Login
- Configuring a Zone for Captive Portal Authentication with RADIUS
- Configuring a Zone for Customized Policy Message
- Configuring a Zone for Customized Login Page
- Configuring the WLAN Zone
- Configuring the RADIUS Server
- Configuring DPI-SSL Granular Control per Zone
- Enabling Automatic Redirection to the User-Policy Page
- Deleting a Zone
- Addresses
- Types of Address Objects
- About Address Groups
- About UUIDs for Address Objects and Groups
- Addresses Page
- Default Address Objects and Groups
- Default Pref64 Address Object
- Default Rogue Address Groups
- Adding an Address Object
- Editing Address Objects
- Deleting Custom Address Objects
- Purging MAC or FQDN Address Objects
- Creating Address Groups
- Editing Address Groups
- Deleting Address Groups
- Working with Dynamic Address Objects
- Services
- About Default Service Objects and Groups
- Predefined IP Protocols for Custom Service Objects
- Adding Service Objects using Predefined Protocols
- Adding Custom IP Type Services
- Editing Custom Service Objects
- Deleting Custom Service Objects
- Adding Custom Service Groups
- Editing Custom Service Groups
- Deleting Custom Service Groups
- URI Lists
- Match Objects
- Schedules
- Dynamic Group
- Email Addresses
- SonicWall Support
Key Features of Dynamic Address Objects
The term Dynamic Address Object (DAO) describes the underlying framework enabling MAC and FQDN AOs. By transforming AOs from static to dynamic structures, access rules can automatically respond to changes in the network.
The below table provides details and examples for DAOs.
| Feature | Benefit |
|---|---|
| FQDN wildcard support |
FQDN address objects support wildcard entries, such as *.somedomainname.com, by first resolving the base domain name to all its defined host IP addresses, and then by constantly actively gleaning DNS responses as they pass through the firewall. For example, creating an FQDN AO for *.myspace.com will first use the DNS servers configured on the firewall to resolve myspace.com to 63.208.226.40, 63.208.226.41, 63.208.226.42, and 63.208.226.43 (as can be confirmed by nslookup myspace.com or equivalent). As most DNS servers do not allow zone transfers, it is typically not possible to automatically enumerate all the hosts in a domain. Instead, the firewall looks for DNS responses coming from sanctioned DNS servers as they traverse the firewall. So, if a host behind the firewall queries an external DNS server that is also a configured/defined DNS server on the firewall, the firewall parses the response to see if it matches the domain of any wildcard FQDN AOs. Sanctioned DNS servers are those DNS servers configured for use by firewall. The reason that responses from only sanctioned DNS servers are used in the wildcard learning process is to protect against the possibility of FQDN AO poisoning through the use of unsanctioned DNS servers with deliberately incorrect host entries. Future versions of SonicOS might offer the option to support responses from all DNS server. The use of sanctioned DNS servers can be enforced with the use of access rules, as described later in Enforcing the Use of Sanctioned Servers on the Network. To illustrate, assume the firewall is configured to use DNS servers 4.2.2.1 and 4.2.2.2, and is providing these DNS servers to all firewalled client via DHCP. If firewalled client-A performs a DNS query against 4.2.2.1 or 4.2.2.2 for vids.myspace.com, the response is examined by the firewall and matched to the defined *.myspace.com FQDN AO. The result (63.208.226.224) is then added to the resolved values of the *.myspace.com DAO. If the workstation, client-A, in the example above had resolved and cached vids.myspace.com before the creation of the *.myspace.com AO, vids.myspace.com would not be resolved by the firewall because the client would use its resolver’s cache rather than issuing a new DNS request. As a result, the firewall would not have the chance to learn about vids.myspace.com unless it was resolved by another host. On a Microsoft Windows workstation, the local resolver cache can be cleared using the command ipconfig /flushdns. This forces the client to resolve all FQDNs, thereby allowing the firewall to learn them as they are accessed. Wildcard FQDN entries resolve all hostnames within the context of the domain name, up to 256 entries per AO. For example, *.sonicwall.com resolves www.sonicwall.com, software.sonicwall.com, and licensemanager.sonicwall.com, to their respective IP addresses, but it does not resolve sslvpn.demo.sonicwall.com because it is in a different context; for sslvpn.demo.sonicwall.com to be resolved by a wildcard FQDN AO, the entry *.demo.sonicwall.com would be required, which would also resolve sonicos-enhanced.demo.sonicwall.com, csm.demo.sonicwall.com, sonicos-standard.demo.sonicwall.com, and so on. Wildcards only support full matches, not partial matches. In other words, *.sonicwall.com is a legitimate entry, but w*.sonicwall.com, *w.sonicwall.com, and w*w.sonicwall.com are not. A wildcard can only be specified once per entry, so *.*.sonicwall.com, for example, is not functional. |
| FQDN resolution using DNS | FQDN address objects are resolved using the DNS servers configured on the firewall in the Network > DNS page. Since it is common for DNS entries to resolve to multiple IP addresses, the FQDN DAO resolution process will retrieve all of the addresses to which a host name resolves, up to 256 entries per AO. In addition to resolving the FQDN to its IPs, the resolution process will also associate the entry’s TTL (time to live) as configured by the DNS administrator. TTL will then be honored to ensure the FQDN information does not become stale. |
| MAC address resolution using live ARP cache data | When a node is detected on any of the firewall’s physical segments through the ARP (Address Resolution Protocol) mechanism, the firewall’s ARP cache is updated with that node’s MAC and IP address. When this update occurs, if a MAC address objects referencing that node’s MAC is present, it will instantly be updated with the resolved address pairing. When a node times out of the ARP cache due to disuse (for example, the host is no longer L2 connected to the firewall) the MAC AO will transition to an unresolved state. |
| MAC address object multi-homing support | MAC AOs can be configured to support multi-homed nodes, where multi-homed refers to nodes with more than one IP address per physical interface. Up to 256 resolved entries are allowed per AO. This way, if a single MAC address resolves to multiple IPs, all of the IP will be applicable to the access rules, etc., that refer to the MAC AO. |
| Automatic and manual refresh processes | MAC AO entries are automatically synchronized to the firewall’s ARP cache, and FQDN AO entries abide by DNS entry TTL values, ensuring that the resolved values are always fresh. In addition to these automatic update processes, manual Refresh and Purge capabilities are provided for individual DAOs, or for all defined DAOs. |
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