Monday 6 September 2010

IPv6 Caveat - Apache & XP

I encountered an interesting problem with my Intranet today.

Certain pages were just hanging halfway through loading. Sure that doesn't sound very exciting but upon inspection of the source code I discovered it was a SOAP call that was hanging.

Trying a manual connection via telnet replicated the hang with an interesting point. It was trying to connect via IPv6. Now I didn't recall manually entering an IPv6 AAAA record into my primary DNS but it so happens that the target machine for this SOAP call is an XP box running the Windows version of the Apache web server and yes, I did recently enabled IPv6 on that machine.

So, diagnosis (yes short post today) is that whilst XP (SP3) supports IPv6 and Apache on other operating systems supports IPv6 it would appear that the two together do not support IPv6. That coupled with Active Directory automatic DNS updates and you have my problem.

The solution was to create a different URL for the SOAP service which only had an IPv4 record and update all the SOAP calls and WSDL files that described the SOAP service in the first place.

So, lesson to be learned, IPv6 support is still lacking despite being around for 15 years. I guess if I'd updated this box to Vista or Windows 7 it might be different but I'm not sure. Before you ask, no I can't install linux, my security vendor doesn't support linux, at least not for this product.

Oh well. Not everything is ready for IPv6 yet.

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