How to configure hostname resolution to use a custom DNS server in Java?

Question

java.net.InetAddress resolves hostnames using the local machine's default host-name resolver by default:

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one . For any host name, its corresponding IP address is returned. ^[source]

How can we configure this behavior without modifying the local machine's default hostname resolver?

For example, is there anyway to configure java.net.InetAddress such that it resolves host names through OpenDNS (208.67.222.222, 208.67.220.220) or Google Public DNS (2001:4860:4860::8888, 2001:4860:4860::8844)?

Or is the only solution to explicitly create DNS packet requests, send them to the servers through either java.net.DatagramSocket or java.net.Socket , and parse the responses?

Answer 1

java.net.InetAddress resolves hostnames using the local machine's default host-name resolver by default:

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one . For any host name, its corresponding IP address is returned. ^[source]

How can we configure this behavior without modifying the local machine's default hostname resolver?

For example, is there anyway to configure java.net.InetAddress such that it resolves host names through OpenDNS (208.67.222.222, 208.67.220.220) or Google Public DNS (2001:4860:4860::8888, 2001:4860:4860::8844)?

Or is the only solution to explicitly create DNS packet requests, send them to the servers through either java.net.DatagramSocket or java.net.Socket , and parse the responses?

Answer 2

java.net.InetAddress resolves hostnames using the local machine's default host-name resolver by default:

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one . For any host name, its corresponding IP address is returned. ^[source]

How can we configure this behavior without modifying the local machine's default hostname resolver?

For example, is there anyway to configure java.net.InetAddress such that it resolves host names through OpenDNS (208.67.222.222, 208.67.220.220) or Google Public DNS (2001:4860:4860::8888, 2001:4860:4860::8844)?

Or is the only solution to explicitly create DNS packet requests, send them to the servers through either java.net.DatagramSocket or java.net.Socket , and parse the responses?

Answer 3

java.net.InetAddress resolves hostnames using the local machine's default host-name resolver by default:

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one . For any host name, its corresponding IP address is returned. ^[source]

How can we configure this behavior without modifying the local machine's default hostname resolver?

For example, is there anyway to configure java.net.InetAddress such that it resolves host names through OpenDNS (208.67.222.222, 208.67.220.220) or Google Public DNS (2001:4860:4860::8888, 2001:4860:4860::8844)?

Or is the only solution to explicitly create DNS packet requests, send them to the servers through either java.net.DatagramSocket or java.net.Socket , and parse the responses?

Answer 4

java.net.InetAddress resolves hostnames using the local machine's default host-name resolver by default:

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one . For any host name, its corresponding IP address is returned. ^[source]

How can we configure this behavior without modifying the local machine's default hostname resolver?

For example, is there anyway to configure java.net.InetAddress such that it resolves host names through OpenDNS (208.67.222.222, 208.67.220.220) or Google Public DNS (2001:4860:4860::8888, 2001:4860:4860::8844)?

Or is the only solution to explicitly create DNS packet requests, send them to the servers through either java.net.DatagramSocket or java.net.Socket , and parse the responses?

Answer 5

As Pace indicated, the ability to configure name resolution was removed from the JDK. However, in Java 18, it was replaced with the SPI java.net.spi.InetAddressResolverProvider .

Between Java 8 and Java 18, as the JDK Inet4AddressImpl.c eventually ends up calling getnameinfo , you can still intercept that call with LD_PRELOAD shadowing.

There are libraries which make this very straightforward, such as CWrap .