What is DNS Blackholing?

What is DNS Blackholing?

DNS sinkhole or black hole DNS is used to spoof DNS servers to prevent resolving hostnames of specified URLs. This can be achieved by configuring the DNS forwarder to return a false IP address to a specific URL. DNS sinkholing can be used to prevent access to malicious URLs at an enterprise level.

What is DNS sinkhole used for?

DNS Sinkholing is a mechanism aimed at protecting users by intercepting DNS request attempting to connect to known malicious or unwanted domains and returning a false, or rather controlled IP address. The controlled IP address points to a sinkhole server defined by the DNS sinkhole administrator.

What is Blackholed domain?

Blackhole DNS servers are Domain Name System (DNS) servers that return a “nonexistent address” answer to reverse DNS lookups for addresses reserved for private use.

How do I create a DNS black hole?

To enable the DNS blackhole feature and configure a DNS blackhole list for a Grid or member:

1. Grid: From the Data Management tab, select the DNS tab, expand the Toolbar and click Grid DNS Properties.
2. In the editor, click the Blackhole tab and complete the following:
3. Select one of the following:
4. Save the configuration.

How does Fortigate DNS filter work?

DNS filtering has the following features:

1. FortiGuard Filtering: filters the DNS request based on the FortiGuard domain rating.
2. Botnet C&C domain blocking: blocks the DNS request for the known botnet C&C domains.
3. External dynamic category domain filtering: allows you to define your own domain category.

What is sinkhole in Palo Alto?

The DNS sinkhole enables the Palo Alto Networks device to forge a response to a DNS query for a known malicious domain/URL and causes the malicious domain name to resolve to a definable IP address (fake IP) that is given to the client.

What type of malware can DNS sinkhole block?

Sinkholes can be used both constructively, to contain threats such as WannaCry and Avalanche, and destructively, for example disrupting DNS services in a DoS attack. One use is to stop botnets, by interrupting the DNS names the botnet is programmed to use for coordination.

What does RBL stand for in email security?

Real-time blackhole list (RBL) is a dynamic list of IP address owners that are active spammers or spam sources. The RBL may include Internet service providers (ISP) with customers that are known spammers or ISP servers that are hijacked for spamming purposes. RBL is also known as a DNS Black List (DNSBL).

What is RBL domain?

A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query whether a sending host’s IP address is blacklisted for email spam.

What is sinkhole IP?

A sinkhole IP address disrupts the flow of unwelcome traffic. By providing incorrect DNS resolution, DNS sinkholing redirects clients attempting to connect to malicious domains or otherwise unwanted content. Sinkholes are very useful for thwarting botnets and their command-and-control (C2) originators.

How do I FortiGate a DNS server?

To configure FortiGate as a primary DNS server in the GUI:

1. Go to Network > DNS Servers.
2. In the DNS Database table, click Create New.
3. Set Type to Master.
4. Set View to Shadow.
5. Enter a DNS Zone, for example, WebServer.
6. Enter the Domain Name of the zone, for example, fortinet.com.

What does DNS filtering do?

DNS filtering is the practice of blocking access to certain sites for a specific purpose, often content-based filtering. If a site, or category of sites, has been deemed a threat, then its IP address is blocked with a DNS filter and access to it is prevented.

What is a DNS-based Blackhole List?

A DNS-based Blackhole List (DNSBL) or Real-time Blackhole List (RBL) is a list of IP addresses published through the Internet Domain Name System (DNS) either as a zone file that can be used by DNS server software, or as a live DNS zone that can be queried in real-time.

How to block malicious URLs using DNS sinkholes?

The malicious URLs can be blocked by adding a false entry in the DNS and thus there will be a second level of protection. Normally firewalls and proxies are used to block malicious traffic across the organization. By using the DNS sinkhole technique it is also possible to deny access to any of the websites.

What is blackholing and how does it work?

With connection oriented protocols like TCP, which require a handshake to connect with the target system, a notification will be returned if the data is dropped. For organizations that have no other means of blocking an attack, blackholing is a widely available option.

What is DNS sinkholing and how does it work?

This can be achieved by configuring the DNS forwarder to return a false IP address to a specific URL. DNS sinkholing can be used to prevent access to malicious URLs at an enterprise level.