CODEWITHSUNDEEP
network-programmingipv6ipv4
YsoL8
YsoL8

Reputation: 2214

Change from IPv4 to IPv6: What are its effects on web development?

Do web developers need to be concerned by the end of IPv4? Or is this strictly a hosting level concern?

What can the average PHP/JavaScript/Ajax etc. developer do to mitigate the impact of the changeover?

Discuss!

(if this has come up before I apologies, but my search revealed nothing)

Upvotes: 9

Views: 972

Answers (4)

plugwash
plugwash

Reputation: 10504

Anywhere you handle IP addresses needs to be audited to check if it is IPv6 clean. Simple webapps may not bother storing any IP addresses but many will for the purposes of abuse tracking/control. IPv6 addresses are larger than ipv4 ones and the textual representations use different symbols.

Under some circumstances IPv4 connections can be handled on an IPv6 socket. In this case you may see "IPv4 mapped addresses" which you may need to convert back to normal IPv4 addresses before storing/comparing them (a lower level process like the webserver may or may not handle this conversion for you).

Dealing with abusers may require some consideration. Banning single addresses is likely futile. For effective banning you will want the ability to ban based on various different prefix lengths. You may also want the ability to map an abusers usage patterns to blocks. Similar problems apply to limits placed on the number of connections per user.

As the IPv4 crunch bites deeper we are likely to see more use of reverse proxy setups to share a limited pool of public IPv4 addresses among v6-only origin servers. Making your software ready for working with reverse proxys is therefore a wise move. This typically means having a list of trusted reverse proxies from which you will accept x-forwarded-for headers.

Upvotes: 1

user207421
user207421

Reputation: 310916

I doubt that IPv4 will ever end, actually. Just my opinion. Netorking apps will have to be written to be IPv4/6 compatible. Some APIs make this exceptionally easy.

Upvotes: 0

Arseny
Arseny

Reputation: 5179

Also, when validating fields for IP addresses, don’t forget to take both formats (152.115.4.70 and 2001:db8:1f70::999:de8:7648:6e8) into account.

Upvotes: 1

bdonlan
bdonlan

Reputation: 231163

On the serverside, make sure you're not making assumptions about the format of the remote IP address - hacks like packing the IP address of a poster in a single 32-bit database field are a bad idea. If you are using subnet masks for bans or something, that will need changes as well.

Upvotes: 8

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