Forum OpenACS Development: Re: NaviServer on Windows: [ns_info address] returns IP v6 address

Collapse
3: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 2)
Posted by Frank Bergmann on 04/11/17 02:41 PM
Hi!

Both machines have valid IPv4 addresses on their primary network adapters, assigned by DHCP.

Hostnames are:
- ws2012 for the Windows Server 2012, and ping ws2012 pings somehow using IPv6.
- "project-open-v50-dev" for my Linux box, and ping project-open-v50-dev pings to 127.0.0.1.

So that's consistent with your explanation on how ns_info address works. And you are right, that doesn't match the man-page text. And it doesn't match the intuition, at least not mine and/or the ]po[ use-case.

Also, with AOLserver 4.5.1 I get the correct ("intuitive") IP address on Windows. I could also swear that it also used to work like this on Linux with ]po[ V4.0.2 (but II can't test right now).

Cheers!
Frank

Collapse
4: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 3)
Posted by Gustaf Neumann on 04/11/17 06:48 PM
Why do you want to get the IPv4 address, when the OS prefers tp report the IPv6 address? It should be possible to use the IPv6 addresses wherever a IPv4 address is in used.

The US is already out of IPv4 addresses [1], so IPv6 will become more visible world-wide (see e.g. [2]). One option seems to be to change the priorities in windows to prefer IPv4 over IPv6 [3,4]. Another option would be to add an option to naviserver "ns_info address -prefer ipv4" (and maybe simiar commands), but in cases, where there is no ipv4 address assigned, this will fail.

-g

[1] https://arstechnica.com/business/2015/09/north-america-is-out-of-ipv4-addresses-for-really-real-this-time/
[2] https://www.google.de/ipv6/statistics.html
[3] https://superuser.com/questions/436574/ipv4-vs-ipv6-priority-in-windows-7
[4] https://social.technet.microsoft.com/Forums/windows/en-US/33b99ca4-9182-4f3d-94ea-7e689c837efe/prefer-ipv4-over-ipv6?forum=winserver8gen

Collapse
5: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 4)
Posted by Frank Bergmann on 04/11/17 07:18 PM
Gustaf,

Nice argument, but sorry, the behavior of ns_info address is
a) incorrect according to the man page,
b) incorrect according to the last AOLserver and
c) incorrect for our use-case.

We can't get much closer to the definition of a bug. And we don't have a single customer who'd enter a IPv6 IP-Address manually in a browser.

I've had to invest another 3 hours to create a robust and multi-platform parser for ifconfig and ipconfig, because I can't wait for you to finish this stuff.

About fixing this command: Let the man page guide you: "Primary IP address of this machine" is a pretty intuitive concept that works in 95% or all cases. Otherwise you've got a pretty useless command in your API...

Cheers,
Frank

Collapse
6: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 5)
Posted by Gustaf Neumann on 04/11/17 07:50 PM
Compile the server without IPv6 support and the "bug" is corrected.
Collapse
7: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 6)
Posted by Frank Bergmann on 04/11/17 08:51 PM
This would still not fix the issue on Linux, where [ns_info address] returns 127.0.0.1.
Why don't you revert to the code in AOLserver?

Cheers,
Frank

Collapse
8: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 7)
Posted by Gustaf Neumann on 04/11/17 09:15 PM
please explain, why you believe the result is incorrect for your Linux box. You mentioned that the hostname of your Linux box is "project-open-v50-dev" and ping project-open-v50-dev pings to 127.0.0.1. So, the result is perfectly correct.
Collapse
9: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 8)
Posted by Frank Bergmann on 04/11/17 09:44 PM
Hi!

I got the "bug" - my bug. I assumed that ns_info address on AOLserver 4.5.1 Linux as intuitively required. But it doesn't. I've just installed AOLserver 4.5.1 and checked.

So both system implement ns_info address in the same way, and reverting wouldn't fix my issue.

Conclusion: You could change the implementation in NaviServer in order to prefer the IPv4 address over the IPv6 address. But otherwise everything is like it was.

=> We'll work with our own implementation of extracting the IP from ifconfig/ipconfig tool output.

Cheers!
Frank

Collapse
10: Re: NaviServer on Windows: [ns_info address] returns IP v6 address (response to 9)
Posted by Gustaf Neumann on 04/17/17 03:42 PM
The easiest way to find all IP-addresses of the the actual hostname is probably:
ns_addrbyhost -all [ns_info hostname]