Forum Discussion
Nimbostratusdns initial setup
I have an existing DNS server and multiple apps servers query this DNS server directly for hostname resolution (via /etc/resolv.conf).
I want to use the F5 in front of the existing DNS server. So, I created the F5 VIP and modified the individual app servers' /etc/resolv.conf to query the F5 VIP instead of the existing DNS server IP. Via F5 admin console, I created a Virtual Server, and a pool with a node (the existing DNS server is the node). But all client nslookup attempts failed; and tcpdump did not show any activities on the F5.
Could you advise what I missed? What's recommended approach to accomplish what I described above?
3 Replies
HamishCirrocumulus
- Does the VS IP address route to the BigIP
- Does the poolmember route back to the client via the BigIP? (Or are you using SNAT?)
I'd use dig to debug myself. Much better than trying to use resolver libraries (Which usually cache. dig doesn't cache).
H
- Kevin_Stewart
Employee
I'd recommend a tcpdump on the F5's external interface to see if 1) the lookups are even making it there, 2) what's going on in the request. Is your VIP set up for UDP port 53?
- Hamish
If you tcpdump between the BigIP and the poolmember, do you see the request being sent to the poolmember FROM the bigIP?
I suspect you maybe don't have SNAT configured, and the poolmember doesn't route back to the client via the BigIP.
H
