Dns Inbound Lb; Chapter 19 Dns Inbound Lb; Dns Inbound Load Balancing Overview; What You Can Do In This Chapter - ZyXEL Communications ZyWall 110 User Manual

19.1 DNS Inbound Load Balancing Overview

Inbound load balancing enables the Zyxel Device to respond to a DNS query message with a different
IP address for DNS name resolution. The Zyxel Device checks which member interface has the least load
and responds to the DNS query message with the interface's IP address.
In the following figure, an Internet host (A) sends a DNS query message to the DNS server (D) in order to
resolve a domain name of www.example.com. DNS server D redirects it to the Zyxel Device (Z)'s WAN1
with an IP address of 1.1.1.1. The Zyxel Device receives the DNS query message and responds to it with
the WAN2's IP address, 2.2.2.2, because the WAN2 has the least load at that moment.
Another Internet host (B) also sends a DNS query message to ask where www.example.com is. The Zyxel
Device responds to it with the WAN1's IP address, 1.1.1.1, since WAN1 has the least load this time.
Figure 347 DNS Load Balancing Example
W
W

19.1.1 What You Can Do in this Chapter

• Use the Inbound LB screen (see
balancing rules.
• Use the Inbound LB Add/Edit screen (see
balancing rule.

DNS Inbound LB

Where is
A:
www.example.com?
Z:
It's 2.2.2.2.
2
1.1.1.1
3
2.2.2.2
Z
Where is
B:
www.example.com?
Z:
It's 1.1.1.1
2
1.1.1.1
3
2.2.2.2
Z
Section 19.2 on page
Section 19.2.1 on page
ZyWALL USG Series User's Guide
484
C
H A P T E R
D
Where is
A:
www.example.com?
1 D:
Ask 1.1.1.1.
D
Where is
B:
www.example.com?
1
D:
Ask 1.1.1.1.
485) to view a list of the configured DNS load
486) to add or edit a DNS load
19
A
B