rc.conf changes IPV6

Dan The Man dan at sunsaturn.com
Tue Nov 22 01:39:37 UTC 2011

On Mon, 21 Nov 2011, Stefan Bethke wrote:

> Am 21.11.2011 um 20:25 schrieb Dan The Man:
>> I notice we have changed way IPV6 is done in rc.conf now.
>> I assume someone will update:
>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-ipv6.html
>> My question now concerns aliases, and what the norm will end up being.
>> Here is example below:
>> Here we have the new layout with IPV6, the below works fine, however since
>> the ifconfig lines for IPV4 and IPV6 are essentially the same other than the actual "inet" and "inet6", will it be ok to start with alias0 for both IPV4 and IPV6, or should I in this example be starting at alias4 for IPV6?
>> I would like idea to keep it way it is each protocal starting at alias0.
>> defaultrouter=""
>> hostname="sunsaturn.com"
>> #IPV4
>> ifconfig_em1="inet netmask"
>> ifconfig_em1_alias0="inet netmask"
>> ifconfig_em1_alias1="inet netmask"
>> ifconfig_em1_alias2="inet netmask"
>> ifconfig_em1_alias3="inet netmask"
>> #IPV6
>> ipv6_activate_all_interfaces="YES"
>> ipv6_network_interfaces="em1"
>> ipv6_defaultrouter="2001:49f0:4004:0000:0000:0000:0000:0001"
>> ifconfig_em1_ipv6="inet6 2001:49f0:4004:0000:0000:0000:0000:0002 prefixlen 48"
>> ifconfig_em1_alias0="inet6 2001:49f0:4004:0000:0000:0000:0000:0003 prefixlen 48"
>> ifconfig_em1_alias1="inet6 2001:49f0:4004:0000:0000:0000:0000:0004 prefixlen 48"
> Remember that rc.conf follows shell syntax and sematics, so the second _alias0 and _alias1 will overwrite the previous ones.
> In 9.0 you can use the ipv4_addrs_<ifname> variable to set both the IPv4 "main" address as well as "alias" addresses, see rc.conf(5).  There doesn't seem to be an equivalent IPv6 option, as best as I can tell.
> Stefan
> -- 
> Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811

You would assume so Stefan, that the duplicate alias0 would overwrite, but 
it seems since ifconfig separates the namespace for IPV4/IPV6 it actually 

Which is good news I would assume, as I have time to time added a new IPV4 
alias, and would have forgotten to update IPV6 alias numbers many times 
unless I revise my config to put ipv4 and ipv6 aliases together in rc.conf 
instead of separating the protocals in there.

I looked at man page, thats a very nice config option ipv4_addrs_<ifname>, 
I agree it would be nice to have an IPV6 equivalent considering how big 
the IPV6 range is.


Dan The Man
CTO/ Senior System Administrator
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Email: Dan at SunSaturn.com

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