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Using IPv6 in Chilkat Apps for iOS

Jun 10 '16 at 08:30

I have just had an app rejected during the App Store approval process because it failed to HTTP download a file when operating on an IPv6 network. This app has been on the Store for a few years – not sure why it would have been rejected just now – must be a new test that they are running.

I have followed all of the instructions at:

This included setting up a private IPv6 network on my Mac. I can verify that downloads that succeed otherwise, fail when attempted on the IPv6 network.

I updated to the very latest version of the chilkat iOS SDK. Do you have any suggestions as to how to get the HTTP download to work on an IPv6 network?


Chilkat should automatically work with IPv6 networks. If the underlying DNS resolution provides both IPv4 and IPv6 choices, then Chilkat will by default choose the IPv4 address. To tell Chilkat to choose the IPv6 choice, set the Http.PreferIpv6 property equal to YES (true). This should solve the problem.

Note: All Chilkat classes that communicate over TCP/TLS will include a PreferIpv6 property. This includes Http, MailMan, Imap, Ftp2, Socket, Ssh, SFtp, etc.