# DNS Load Balancing (Issue with Round Robin Algorithm)
**URL:** https://community.a10networks.com/t/dns-load-balancing-issue-with-round-robin-algorithm/454
**Category:** ADC - Application Delivery
**Tags:** dns, slb-adc
**Created:** [June 20, 2017, 4:27pm UTC](https://community.a10networks.com/t/dns-load-balancing-issue-with-round-robin-algorithm/454 "2017-06-20T16:27:14Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Morphius](https://community.a10networks.com/u/Morphius)
#### Post date: [June 20, 2017, 4:27pm UTC](https://community.a10networks.com/t/dns-load-balancing-issue-with-round-robin-algorithm/454/1 "2017-06-20T16:27:14Z")
Hi
I’m having some issues with DNS-Load Balncing. I’m using Thunder 3030s (ADC) right now and i’m on a beginner level. The configurations are quite simple (L-4).
We need to load balance Port-53 Queries between 2 Real Servers. The issue that i’m having is that, when the VIP is hit. The request terminates on both Real Servers at a same time inspite of ROUND ROBIN STRICT or ROUND ROBIN Algorithm.
Following are the current configurations. It would be great if i can get some guidance concerning to this.
```auto
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
interface ethernet 1 (\*\*Towards Internet\*\*)
```
enable
ip address 10.10.10.252 255.255.255.0
!
!
ip route 0.0.0.0 /0 10.10.10.1
!
health monitor tcp
method tcp port 53
!
health monitor udp
method udp port 53
!
slb server internal-server 10.10.10.254
health-check ping
port 53 tcp
port 53 udp
!
slb server server 212.249.200.135
health-check ping
port 53 tcp
port 53 udp
!
```auto
slb service-group service-tcp tcp
method round-robin-strict
```
health-check ping
member internal-server 53
member server 53
!
```auto
slb service-group service-udp udp
method round-robin-strict
```
health-check ping
member internal-server 53
member server 53
!
slb virtual-server DNS-vip 10.10.10.233
port 53 dns-udp
name UDP
source-nat auto
service-group service-udp
port 53 dns-tcp
name TCP
source-nat auto
```auto
service-group service-tcp
\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
```
Thanks.
---
### Author:  [@ehteshammalik007](https://community.a10networks.com/u/ehteshammalik007)
#### Post date: [June 21, 2017, 9:14am UTC](https://community.a10networks.com/t/dns-load-balancing-issue-with-round-robin-algorithm/454/2 "2017-06-21T09:14:27Z")
i am also suffering from the same issue when i test DNS(VIP) using nslookup
against single query 4 hits/connection are established on VIP.
I dont exactly know the issue right now. Why the VIP is getting 4 HITS against 1-single NSLOOKUP Query.