关掉jvm的ipv6功能 - 王朝网络宽屏版

1。关掉jvm的ipv6功能

jvm加以下参数：-Djava.net.preferIPv4Stack=true

Issues with JGroups and IPv6 on Linux

In a nutshell: IPv6 works with JGroups !

On Windows (XP), you have to enable IPv6 by clicking on any connection (e.g. "Local Area Connection") --> Properies --> Install --> Protocol --> IPv6. If you do ipconfig, you will see the new IPv6 addresses. By default, WinXP? seems to prefer IPv6.

On Linux, IPv6 doesn't work (see below) due to a bug

in the JDKs up to and including JDK 5. Mustang (JDK 6) fixed this, and I verified that it works on RHAT fedora core 5 . So, on Linux, with SUN's VM, you *have* to use -Djava.net.preferIPv4Stack=true, until you switch to JDK 6. I haven't tried this on JRockit or IBM's VM.

Here is the Jira issues: http://jira.jboss.com/jira/browse/JGRP-47

IP_MULTICAST_IF:

java.net.SocketException: bad argument for IP_MULTICAST_IF: address not bound to any interface

at java.net.PlainDatagramSocketImpl.socketSetOption(Native Method)

at java.net.PlainDatagramSocketImpl.setOption(PlainDatagramSocketImpl.java:295)

There was an earlier post mentioning the same symptoms. Assuming that you are running JBoss on Linux, if your Linux kernel has IPv6 support, you will have this problem. If you don't need IPv6 support, you can disable it from the kernel and the problem will go away.

Turn off IPv6 in the Linux kernel

To disable IPv6 in the kernel (or really, disable automatic loading of the IPv6 module - see here for IPv6 and Linux details

for details), add the following line in your modules config file :

alias net-pf-10 off # disable automatically load of IPv6 module on demand

For 2.4 kernels, this would be in /etc/modules.conf or /etc/conf.modules. For 2.6 kernels, this would be in /etc/modprobe.conf or /etc/modprobe.conf.local (for SLES). You need to reboot the Linux box. I'm not sure of another way to disable this without a reboot. If you know of any, please update this page or add a link to some further docs on the subject.

Also, once you disable this in the kernel, you can still enable IPv6 on an interface by following these instructions

(for RedHat? at least).

Turn off IPv6 in the JVM

Another source of problems might be the use of IPv6, and/or misconfiguration of /etc/hosts. If you communicate between an IPv4 and an IPv6 host, and they are not able to find each other, try the java.net.preferIP4Stack=true property, e.g.

java -Djava.net.preferIPv4Stack=true org.jgroups.demos.Draw

JDK 1.4.1 uses IPv6 by default, although is has a dual stack, that is, it also supports IPv4. Here's

more details on the subject.

IPv6 and IP Bonding

Looks like turning IPv6 off also has the nice side effect that IP Bonding works (it doesn't work with IPv6 turned on). This is anecdotal (from a customer support case), and we need to verify this in the 2.3/2.4 time frame

IPv6 support

Due to a bug

in the JDK on Linux, a socket cannot be bound to an IPv6 address. This is the reason why -Djava.net.preferIPv4Stack=true has to be used. This bug is supposedly fixed in Mustang (JDK 6). JGroups, starting from version 2.3, supports IPv6. The change from previous versions was mainly how we marshalled IpAddresses?.