Inbound Load Balancing; Inbound Load Balancing Overview; What You Can Do In This Chapter - ZyXEL Communications 310 User Manual

17.1 Inbound Load Balancing Overview

Inbound load balancing enables the ZyWALL to respond to a DNS query message with a different IP
address for DNS name resolution. The ZyWALL 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 ZyWALL
(Z)'s WAN1 with an IP address of 1.1.1.1. The ZyWALL 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
ZyWALL responds to it with the WAN1's IP address, 1.1.1.1, since WAN1 has the least load this
time.
Figure 145 DNS Load Balancing Example
W
W

17.1.1 What You Can Do in this Chapter

• Use the Inbound LB screen (see
load balancing rules.
ZyWALL 110/310/1100 Series User's Guide
C

Inbound Load Balancing

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 2.2.2.2.
2
1.1.1.1
3
2.2.2.2
Z
Section 17.2 on page
HAPTER
D
Where is
A:
www.example.com?
1 D:
Ask 1.1.1.1.
Internet
D
Where is
B:
www.example.com?
1
D:
Ask 1.1.1.1.
Internet
248) to view a list of the configured DNS
1 7
A
B
247