Rod Whitworth [glis...@witworx.com] wrote: > I'm looking after a bgpd setup which announces an IPv6 /32 and an IPv4 > /21. > > Due to a need for some heavy traffic clients to have their traffic > arrive via just one transit I'd like to turn that /21 into a /22 and > two /23s and only advertise one of the /23s via the "heavy traffic" > transit. >
Here's an example that might work. You can twist it around depending on how localpref is setup with your providers to make it work better. If you happen to also be using "network inet static" (redistribute static routes via BGP) and you happen to be statically routing these same subnets beyond your router, you will run into this bug: http://cvs.openbsd.org/cgi-bin/query-pr-wrapper?full=yes&numbers=6406 # policy: # community 2:100 announced to all ebgp peers # community 2:99 announced to 12.1.1.1 only # community 2:98 announced to 44.4.4.5 only network 2709:fe00::0/32 set community 2:100 network 35.0.0.0/21 set community 2:100 network 35.0.0.0/23 set community 2:98 network 35.0.2.0/23 set community 2:99 network 35.0.4.0/22 set community 2:99 neighbor 12.1.1.1 { remote-as 7018 local-address 12.1.1.2 announce all } neighbor 44.4.4.5 { remote-as 9910 local-address 44.4.4.6 announce all } deny to 12.1.1.1 allow to 12.1.1.1 community 2:100 allow to 12.1.1.1 community 2:98 deny to 44.4.4.5 allow to 44.4.4.5 community 2:100 allow to 44.4.4.5 community 2:99 If you only have one bgp-speaking router, using communities isn't as helpful, you might want to remove that layer of abstraction: network 2709:fe00::0/32 network 35.0.0.0/21 network 35.0.0.0/23 network 35.0.2.0/23 network 35.0.4.0/22 neighbor 12.1.1.1 { remote-as 7018 local-address 12.1.1.2 announce all } neighbor 44.4.4.5 { remote-as 9910 local-address 44.4.4.6 announce all } deny to 12.1.1.1 allow to 12.1.1.1 prefix { 35.0.0.0/21 35.0.0.0/23 } deny to 44.4.4.5 allow to 44.4.4.5 prefix { 35.0.0.0/21 35.0.2.0/23 35.0.4.0/22 } > I'm on some medication that makes me dopier than usual but I can't even > see a vague hint in man bgpd.conf. Is it possible? > Heh... Time to get off the medication Chris
