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[mpetach]

I've been trying different versions of 12.2 software, and so far, none
of them have supported IPv6.  Is there some super-secret build I need
to request to get IPv6 support?

[carrerasg]

I'm no expert by any means and Cisco has the most confusing versioning system I've ever seen.  I believe that you need at least a version 12.4 or 12.3(t). If I remember right the t series are like a development branch.

[mpetach]

I'm no expert by any means and Cisco has the most confusing versioning system I've ever seen.  I believe that you need at least a version 12.4 or 12.3(t). If I remember right the t series are like a development branch.

Excellent!  I'll see if I can find a version of the "T" train that still exists, then.  Wish Cisco didn't have such an alphabet soup of software versions.  ^_^;
Thanks!

[carrerasg]

Just to clarify, since it looks like I didn't write that clearly enough.  I *think* ALL 12.4 versions support IPV6, but in the 12.3 versions, only the (t) series has that support.  Granted, this info is from my usually bad memory so try to verify that if you can. The Cisco website has that information but it literally took me hours to figure out what I needed to know when I did it two months.

[pbrutsch]

mpetach, a Cisco 4700 is a very very very very old router that Cisco stopped supporting after 12.2; you won't find an IOS release for it that supports IPv6.

carrerasg, IOS 12.3 does indeed support IPv6, but you need to make sure you pick the right feature set. The same goes for 12.4 - IIRC at a minimum you need Advanced IP Services.

If you want a cheap (for various definitions of cheap ) Cisco router that supports IPv6, here are some examples:
various 1700 series, specifically the 1721, 1751 or 1760
2600XM series
2691
3725 or 3745
1800 series

If you get lucky you might find a 2611XM on eBay for under $200 + shipping. Try go to with a reputable vendor, they are usually willing to work with you on the feature set as well as the RAM and flash requirements for the image.