Re: -06 candidate

[Brian E Carpenter <[e-mail]>]

On 2012-01-18 11:26, Mark Andrews wrote:
> ULA need to be de-preferenced except for the local ULA prefixes.
> 
> Below is what I use in FreeBSD 8.  It keeps local traffic using
> fd92:7065:b8e::/48 rather than using the PA address.  If you learn
> a ULA destination address that is not local YOU DO NOT WANT TO USE
> IT by default when you have another choice.

Not true if you have a VPN link to a business partner and you want
your traffic to that partner to use the ULA, which is routed via
the VPN, rather than a GUA that is routed via the Internet.

Not true if an enterprise uses multiple ULA prefixes internally
for some reason.

These cases will need explicit policy table entries if the default
is de-pref as you suggest.

    Brian
> 
> What you do want is for a interface when it learns a ULA address
> to add the corresponding /48 prefix with a given precedence and a
> unique label to the table if the prefix does not exist.  And
> appropriate cleaning be done when no more interfaces exist in the
> /48.  This may require a manual tag on table entries.
> 
> Mark
> 
>>   more /etc/ip6addrctl.conf 
> #Prefix                          Prec Label     
> ::1/128                           50     0
> ::/0                              40     1     
> 2002::/16                         30     2        
> ::/96                             20     3        
> ::ffff:0.0.0.0/96                 35     4        
> fd92:7065:b8e::/48                45     5 
> fc00::/7                          5      6
>> ifconfig nfe0 inet6
> nfe0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 	options=82008<VLAN_MTU,WOL_MAGIC,LINKSTATE>
> 	inet6 fe80::218:f3ff:feba:9a37%nfe0 prefixlen 64 scopeid 0x5 
> 	inet6 fd92:7065:b8e:0:218:f3ff:feba:9a37 prefixlen 64 autoconf 
> 	inet6 2001:470:1f00:820:218:f3ff:feba:9a37 prefixlen 64 autoconf