As you must be aware that IPv4 addresses ar almost over and the switch to IPv6 is imminent, should I, as a programmer need to worry about anything to make my applications work with the new system ?

Please pardon my ignorance. Its always better to ask and learn than pretending to know-it-all.

  • The first time somebody said this to me was over a decade ago in my Cisco class. Here it is 2011 and I am still surprised any time I actually see an ipv6 address. "Your toaster will have an IP"..uhu.. Feb 7, 2011 at 15:02
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    Well, at least nowadays our desktops are shipping with IP6 stacks built in, and on by default. Feb 7, 2011 at 16:10

2 Answers 2


The short answer: yes

The longer answer: depends on what your applications are doing.

  • How are your applications handling networking?
  • Are you doing IPv4 manipulations?
  • What languages are your applications written in?
  • Are the libraries IPv6 safe?
  • Are your data structures specific to IPv4, or are they flexible?

Every programmer writing internet-aware applications should, at the very least, be aware of IPv6. Whether IPv6 affects the code you're responsible for requires a lot more information.

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    It's not so much the languages in which you write but (as your next point hints at) what the libraries your language uses are like. Feb 7, 2011 at 14:42

Your code should be written to use IPv6 interfaces; these will work with IPv4 too. The IPv6 APIs tend to be better organized than the IPv4 ones, too. The APIs allow you to work with IPv4 networks as well as IPv6 ones.

The main difference is when printing addresses: IPv4 dotted decimal ( notation does have an analogue in IPv6, but it is more complex (and longer because the addresses are 128 bits instead of 32 bits). Host names are recommended for IPv6.

Possible IPv6 address notations:

  • 0013:2124::0319 (abbreviated)
  • 0013:2124:0000:0000:0000:0000:0000:0319 (longhand for previous address)

There are a number of variant address formats, including IPv4 transitional aids.

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