Carsten_Schmitz

Automic 12.1 requires IPV6 - thoughts?

Discussion created by Carsten_Schmitz on Oct 2, 2017
Latest reply on Apr 3, 2018 by NicoleBöger605686
Hi.

I'm just in the process of "installing" the shiny new version 12.1.

I have found the following exciting tidbit in the change notes between 12.0 and 12.1:

   "AF_INET6 (Address family IPv6) is mandatory for all components in V12.1.0."

That's quite a major change for a minor release, seeing as how many companies (including my own) seem to like to pretent IPv6 will go away again if nobody looks at it too directly.

I have, however, previously seen a distinct problem with this combination of applications enabling IPv6 support and companies having broken IPv6 setups:

For added IPv6 support in applications to make any sense, manufacturers need to make IPv6 the default method. The application then starts to do, for example, IPv6 DNS lookups (AAAA queries) by default. Many a companies broken IPv6 setup meant that this runs into a timeout before returning, and the application will only then try IPv4 as the fallback mechanism. Thus, the application hangs for, say, 30 seconds every time it does a DNS lookup. This is, partially, the reason why many tools and applications in Linux have a distinct switch to disable IPv6 support.

V12.1 is fresh and I haven't had a long test run with it yet, and it remains to be seen if Automic defaults to IPv6 and if so, runs into any such issues for someone. But I'd like to point out this possibility, and pose these question to the community, and Automic:

  • out of curiosity, is your company ready for IPv6 across the entire Automic landscape (including agent machines?)
  • please share your experiences with 12.1 and IPv6 in this thread, if any
  • mostly at Automic: will 12.1 default to IPv6 over IPv4 with ANY functionality in ANY component, and if so, can the use of IPv6 be disabled at application level (and if so: how?)
Thanks.


p.s. and mostly at Automic:

Your release notes tell the user to check "dmesg | grep ipv6t". This is not significant. dmesg is a ring buffer, and things rotate out of ring buffers. On my server, for example, this returns nothing eventhough I believe my kernel DOES have IPv6 support in the kernel, but not bound to any interfaces.

A better test may be to check for the presence of /proc/net/if_inet6.

p.p.s. yes, I definetly have IPv6 support in kernel, because:

# netstat -anp | grep ucybsm
tcp6       0      0 :::8871                 :::*                    LISTEN      3922/ucybsmgr
udp6       0      0 :::8871                 :::*                                3922/ucybsmgr

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