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Choose ipv4 or ipv6 google dns servers as default fallback based on the settings for this system / jvm

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Motivation:

We should not use ipv4 google dns servers if the app is configured to run ipv6.

Modifications:

Use either ipv4 or ipv6 dns servers depending on the system config.

Result:

More correct behaviour
This commit is contained in:
Norman Maurer 2017-07-25 21:14:55 +02:00
parent efb2d141c1
commit 359beff56f
1 changed files with 17 additions and 4 deletions
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13
resolver-dns/src/main/java/io/netty/resolver/dns/DefaultDnsServerAddressStreamProvider.java
View File

@ -15,6 +15,7 @@
*/
package io.netty.resolver.dns;
import io.netty.util.NetUtil;
import io.netty.util.internal.SocketUtils;
import io.netty.util.internal.UnstableApi;
import io.netty.util.internal.logging.InternalLogger;
@ -25,6 +26,7 @@ import javax.naming.NamingException;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
import java.lang.reflect.Method;
import java.net.Inet6Address;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URISyntaxException;
@ -116,11 +118,22 @@ public final class DefaultDnsServerAddressStreamProvider implements DnsServerAdd
logger.debug(
"Default DNS servers: {} (sun.net.dns.ResolverConfiguration)", defaultNameServers);
}
} else {
// Depending if IPv6 or IPv4 is used choose the correct DNS servers provided by google:
// https://developers.google.com/speed/public-dns/docs/using
// https://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html
if (NetUtil.isIpV6AddressesPreferred() ||
(NetUtil.LOCALHOST instanceof Inet6Address && !NetUtil.isIpV4StackPreferred())) {
Collections.addAll(
defaultNameServers,
SocketUtils.socketAddress("2001:4860:4860::8888", DNS_PORT),
SocketUtils.socketAddress("2001:4860:4860::8844", DNS_PORT));
} else {
Collections.addAll(
defaultNameServers,
SocketUtils.socketAddress("8.8.8.8", DNS_PORT),
SocketUtils.socketAddress("8.8.4.4", DNS_PORT));
}
if (logger.isWarnEnabled()) {
logger.warn(