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• Predefined IP Address—A predefined IP address list is a type of IP address list that refers to the built-in, dynamic IP lists with fixed or “predefined” contents. These Built-In External Dynamic Lists—for bulletproof hosting providers, known malicious, and high-risk IP addresses—are automatically added to your firewall if you have an active Threat Prevention license. A predefined IP address list can also refer to an EDL that uses one of the built-in lists as a source. Because you can’t modify the contents of a predefined list, you might use one as a source for a different EDL if you want to add or exclude list entries.
• IP Address—The firewall typically enforces policy for a source or destination IP address that is defined as a static object on the firewall (see Enforce Policy on an External Dynamic List) If you need agility in enforcing policy for a list of source or destination IP addresses that emerge ad hoc, you can use an external dynamic list of type IP address as a source or destination address object in policy rules, and configure the firewall to deny or allow access to the IP addresses (IPv4 and IPv6 address, IP range and IP subnets) included in the list. You can also use an IP address EDL in the source or destination of an SD-WAN policy rule. The firewall treats an external dynamic list of type IP address as an address object; all the IP addresses included in a list are handled as one address object.
• Domain—An external dynamic list of type domain allows you to import custom domain names into the firewall to enforce policy using an Anti-Spyware profile or SD-WAN policy rule. An EDL in an Anti-Spyware profile is very useful if you subscribe to third-party threat intelligence feeds and want to protect your network from new sources of threat or malware as soon as you learn of a malicious domain. For each domain you include in the external dynamic list, the firewall creates a custom DNS-based spyware signature so that you can enable DNS sinkholing. The DNS-based spyware signature is of type spyware with medium severity and each signature is named Custom Malicious DNS Query <domain name>. You can also specify the firewall to include the subdomains of a specifed domain. For example, if your domain list includes paloaltonetworks.com, all lower level components of the domain name (e.g., *.paloaltonetworks.com) will also be included as part of the list. When this setting is enabled, each domain in a given list requires an additional entry, effectively doubling the number of entries used by the list. For details on configuring domain lists, see Configure DNS Sinkholing for a List of Custom Domains.
• URL—An external dynamic list of type URL gives you the agility to protect your network from new sources of threat or malware. The firewall handles an external dynamic list with URLs like a custom URL category and you can use this list in two ways:
  • As a match criterion in Security policy rules, Decryption policy rules, and QoS policy rules to allow, deny, decrypt, not decrypt, or allocate bandwidth for the URLs in the custom category.
  • In a URL Filtering profile where you can define more granular actions, such as continue, alert, or override, before you attach the profile to a Security policy rule (see Use an External Dynamic List in a URL Filtering Profile).

• IP address—The PA-3200 Series, PA-5200 Series, and the PA-7000 Series firewalls support a maximum of 150,000 total IP addresses; all other models support a maximum of 50,000 total IP addresses. No limits are enforced for the number of IP addresses per list. When the maximum supported IP address limit is reached on the firewall, the firewall generates a syslog message. The IP addresses in predefined IP address lists do not count toward the limit.
• URL and domain—The maximum number of URLs and domains supported varies by model. No limits are enforced for the number of URL or domain entries per list. Refer to the following table for specifics on your model:

  Model	URL List Entry Limits	Domain List Entry Limits
  PA-5200 Series, PA-7000 Series (upgraded with the PA-7000 20GXM NPC, PA-7000 20GQXM NPC, or the PA-7000 100G NPC). PA-7000 appliances with mixed NPCs only support the standard capacities.	250,000	4,000,000
  VM-500, VM-700	100,000	2,000,000
  PA-850, PA-820, PA-3200 Series	100,000	1,000,000
  PA-7000 Series (and appliances upgraded with the PA-7000 20GQ NPC or the PA-7000 20G NPC), VM-300	100,000	500,000
  PA-220, VM-50, VM-50 (Lite), VM-100, VM-1000-HV	50,000	50,000