nanog mailing list archives
Re: using ULA for 'hidden' v6 devices?
From: Mark Andrews <marka () isc org>
Date: Thu, 26 Jan 2012 09:51:13 +1100
In message <Pine.LNX.4.64.1201251037480.16219 () whammy cluebyfour org>, "Justin M . Streiner" writes:
Is anyone using ULA (RFC 4193) address space for v6 infrastructure that does not need to be exposed to the outside world? I understand the concept of having fc00::/8 being doled out by the RIRs never went anywhere, and using space out of fd00::/8 can be a bit of a crap-shoot because of the likelihood of many organizations that do so not following the algorithm for picking a /48 that is outlined in the RFC. There would appear to be reasonable arguments for and against using ULA. I'm just curious about what people are doing in practice. jms
A lot has to do with whether you have PA addresses of not. As for picking a random prefix I suspect most home CPE devices will do the right thing. It's also easy to do the right thing. I just did "dd if=/dev/random count=1 bs=5 | od -x" and pulled the hex dig digits out to construct the ULA I use at home. A little bit prettier version is below. #!/bin/sh dd bs=5 count=1 if=/dev/random 2> /dev/null | od -t x1 | awk 'NF == 6 { print "f8" $2 ":" $3 $4 ":" $5 $6 }' If you don't want to use /dev/random (ifconfig -a ; date ; netstat -na) | md5 | sed 's/\(..\)\(....\)\(....\).*/f8\1:\2:\3/' There are lots of ways to generate a suitable prefix. -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka () isc org
Current thread:
- Re: using ULA for 'hidden' v6 devices?, (continued)
- Message not available
- Re: using ULA for 'hidden' v6 devices? Tim Chown (Jan 26)
- Re: using ULA for 'hidden' v6 devices? Owen DeLong (Jan 26)
- Re: using ULA for 'hidden' v6 devices? Valdis . Kletnieks (Jan 26)
- Re: using ULA for 'hidden' v6 devices? Robert E. Seastrom (Jan 31)
- "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) Jeroen Massar (Jan 25)
- Re: "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) William Herrin (Jan 25)
- Re: "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) Jeroen Massar (Jan 25)
- Re: "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) William Herrin (Jan 25)
- Re: "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) Jeroen Massar (Jan 25)
- Re: "Registered ULA" (Was: using ULA for 'hidden' v6 devices?) William Herrin (Jan 25)