08-18-2015 11:31 AM
We are testing DNS Anycast using OSPF; However, we have legacy portions of our network that don't run OSPF, but run EIGRP. Has anyone had any experience with redistributing DNS Anycast from OSPF to EIGRP and then back? Any issues?
08-18-2015 12:19 PM
Not quite what you are looking for but we use OSPF for anycast DNS and NTP within regions, but redistrubute between regions via BGP.
Our only issue is with costing in BGP. We have issues where the "clostest" via RTT is not the clostest cost via BGP and we had no easy way to fix it.
Things like our South Amerian sites perfer our Europe or Asia anycast during a failure instead of the lowest RTT of the US anycast instances. But functionally, we have seen no issues with the anycast and a combination of BGP and OSPF, BGP just has some limitations in our environmet in controlling where we would like some things to fail between regions.
08-18-2015 07:17 PM
We have been redistributing OSPF into EIGRP for this very reason.
EIGRP config snippet: redistribute ospf myOspfInstance route-map ospf_to_eigrp
We use the route-map ospf_to_eigrp to limit the redistribution to the /32 host routes for all the anycast addresses we have configured and deny everything else.
I has been working for 3 years with no issues.
If you want specific configurations drop me an email: firstname.lastname@example.org
08-21-2015 10:16 AM