Ruby has already the needed Regex in the standard library. Checkout resolv. require “resolv” “192.168.1.1” =~ Resolv::IPv4::Regex ? true : false #=> true “192.168.1.500” =~ Resolv::IPv4::Regex ? true : false #=> false “ff02::1” =~ Resolv::IPv6::Regex ? true : false #=> true “ff02::1::1” =~ Resolv::IPv6::Regex ? true : false #=> false If you like it the … Read more
You can use System.setProperty(“java.net.preferIPv4Stack” , “true”); This is equivalent to passing it in the command line via -Djava.net.preferIPv4Stack=true
I looked through the older IPv6 RFCs in order to find a clue about the history, but I think the answer lies in RFC 4291 section 2.2.3: 3. An alternative form that is sometimes more convenient when dealing with a mixed environment of IPv4 and IPv6 nodes is x:x:x:x:x:x:d.d.d.d, where the ‘x’s are the hexadecimal … Read more
I found myself asking this question and from all the posts I read never found any performance comparisons. So here’s my attempt. I’ve created the following tables, populated with 2,000,000 random ip address from 100 random networks. CREATE TABLE ipv6_address_binary ( id SERIAL NOT NULL AUTO_INCREMENT PRIMARY KEY, addr BINARY(16) NOT NULL UNIQUE ); CREATE … Read more
As the docs say, Begin accepting connections on the specified port and hostname. If the hostname is omitted, the server will accept connections on any IPv6 address (::) when IPv6 is available, or any IPv4 address (0.0.0.0) otherwise. A port value of zero will assign a random port. So, the following code would print running … Read more
With nslookup, just query for the AAAA record type used for IPv6 addresses: nslookup -query=AAAA $hostname
The more generic solution (that also works for BSD) is to edit the global /etc/ssh/ssh_config or per-user ~/.ssh/config and add/replace the entry: AddressFamily any with the following line (where inet corresponds to ipv4): AddressFamily inet You can also set this for just a single host: Host example.com AddressFamily inet
This was caused by an IPv6 address being returned from java.net.NetworkInterface.getDefault(). I’m on a Macbook and was using wireless — p2p0 (used for AirDrop) was returned as the default network interface but my p2p0 only has an IPv6 ether entry (found by running ipconfig). Two solutions, both of which worked for me (I prefer the … Read more
I wanted to use this for some program I hadn’t control for running that Java app so ended with this _JAVA_OPTIONS=-Djava.net.preferIPv4Stack=true environment variable. (read about _JAVA_OPTIONS here) If you are using Windows, just run this command on Windows cmd: setx _JAVA_OPTIONS -Djava.net.preferIPv4Stack=true Thanks to Jason Nichols for reminding this JVM argument 🙂
Have you looked at all the addresses in the return, discard the ones of family InterNetworkV6 and retain only the IPv4 ones?