ipv6

How can I disable IPv6 stack use for IPv4 IPs on JRE?

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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 🙂

What is IPV6 for localhost and 0.0.0.0?

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As we all know that IPv4 address for localhost is 127.0.0.1 (loopback address). Actually, any IPv4 address in 127.0.0.0/8 is a loopback address. In IPv6, the direct analog of the loopback range is ::1/128. So ::1 (long form 0:0:0:0:0:0:0:1) is the one and only IPv6 loopback address. While the hostname localhost will normally resolve to … Read more

How to convert IPv6 from binary for storage in MySQL

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We went for a VARBINARY(16) column instead and use inet_pton() and inet_ntop() to do the conversions: https://github.com/skion/mysql-udf-ipv6 The functions can be loaded into a running MySQL server and will give you INET6_NTOP and INET6_PTON in SQL, just as the familiar INET_NTOA and INET_ATON functions for IPv4. Edit: There are compatible functions in MySQL now, just … Read more

Force requests to use IPv4 / IPv6

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I’ve found a minimalistic solution to force urrlib3 to use either ipv4 or ipv6. This method is used by urrlib3 for creating new connection both for Http and Https. You can specify in it any AF_FAMILY you want to use. import socket import requests.packages.urllib3.util.connection as urllib3_cn def allowed_gai_family(): “”” https://github.com/shazow/urllib3/blob/master/urllib3/util/connection.py “”” family = socket.AF_INET if … Read more

Make docker use IPv4 for port binding

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As @daniel-t points out in the comment: github.com/docker/docker/issues/2174 is about showing binding only to IPv6 in netstat, but that is not an issue. As that github issues states: When setting up the proxy, Docker requests the loopback address ‘127.0.0.1’, Linux realises this is an address that exists in IPv6 (as ::0) and opens on both … Read more

required iPv6 compatibility – iOS app rejected by apple

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If you are using IPv4-specific APIs or hard-coded IP addresses, you will need to update your code, Although all NSURLSession and CFNetwork APIs(including NSURLConnection) already support IPV6 As mentioned by Apple: At WWDC 2015 we announced the transition to IPv6-only network services in iOS 9. Starting June 1, 2016 all apps submitted to the App … Read more

Maximum length of the textual representation of an IPv6 address?

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45 characters. You might expect an address to be 0000:0000:0000:0000:0000:0000:0000:0000 8 * 4 + 7 = 39 8 groups of 4 digits with 7 : between them. But if you have an IPv4-mapped IPv6 address, the last two groups can be written in base 10 separated by ., eg. [::ffff:192.168.100.228]. Written out fully: 0000:0000:0000:0000:0000:ffff:192.168.100.228 (6 … Read more

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