Forum Discussion
SolarJeans
Cirrus
CirrusF5 DNS Links
Hello Experts, My F5 DNS now has 1 link to internet, now I am planning to add 1 more internet link to F5 DNS so it can be resilience. Under DNS -> GSLB: Links -> Link List, can I add the additional...
SolarJeansCirrus
CirrusThank you.
I am a little bit confused, so this cannot be done in dns, and need provision lc function?
As 2 ISP links are located in same DC, and if both links are up, it will be round robin.
What I concern is, if 1 ISP link down, will DNS still look for down link and reply the down link public IP? As my health mon will monitor the internal server and will show up even ISP link down. Or can I assign 2 health mon profiles in same virtual servers? One is monitoring ISP public IP and one is monitoring internal server IP, if 2 profiles assigned, this will monitor both profiles or either one?
Paulius
MVP
MVPSolarJeans Is this new ISP connection going to your GTM or a different device? If this is going to your GTM and one of the links goes down on the GTM and you have ECMP configured it will just use the other connection. If you have monitors also that will allow you to mark a link down because that ISP is having issues that can also bring the link down and only use the one. From the client side of DNS queries they will have a DNS response that shows both IPs but the client will query 1 and if the query fails it will query the other records because of how DNS queries work. So you cannot deal with your redundant links by just GTM DNS but you can achieve this using ECMP, some SLA monitors on the GTM, and then DNS records that show what the authoritative NSs are for the zone in question.