HP OfficeConnect Firewall Series Manuel d'utilisateur télécharger pdf (Page 44)

Chapter 5. Configuring LAN Settings OfficeConnect VPN Firewall User’s Manual

Figure 5.4 Host Discovery Configuration Page

5.4 DNS

5.4.1 About DNS

Domain Name System (DNS) servers map the user-friendly domain names that

users type into their Web browsers (e.g., "yahoo.com") to the equivalent

numerical IP addresses that are used for Internet routing.

When a PC user types a domain name into a browser, the PC must first send a

request to a DNS server to obtain the equivalent IP address. The DNS server will

attempt to look up the domain name in its own database, and will communicate

with higher-level DNS servers when the name cannot be found locally. When the

address is found, it is sent back to the requesting PC and is referenced in IP

packets for the remainder of the communication.

5.4.2 Assigning DNS Addresses

Multiple DNS addresses are useful to provide alternatives when one of the

servers is down or is encountering heavy traffic. ISPs typically provide primary

and secondary DNS addresses, and may provide additional addresses. Your

LAN PCs learn these DNS addresses in one of the following ways:

 Statically: If your ISP provides you with their DNS server addresses, you

can assign them to each PC by modifying the PCs' IP properties.

 Dynamically from a DHCP pool: You can configure the DHCP Server the

OfficeConnect Gigabit VPN Firewall and create an address pool that

specify the DNS addresses to be distributed to the PCs. Refer to the

section Configuring DHCP Server on page 27 for instructions on creating

DHCP address pools.

In either case, you can specify the actual addresses of the ISP's DNS servers

(on the PC or in the DHCP pool), or you can specify the address of the LAN port

on the OfficeConnect Gigabit VPN Firewall (e.g., 192.168.1.1). When you

specify the LAN port IP address, the device performs DNS relay, as described in

the following section.

Note

If you specify the actual DNS addresses on the PCs or in the

DHCP pool, the DNS relay feature is not used.

5.4.3 Configuring DNS Relay

When you specify the device's LAN port IP address as the DNS address, then

the OfficeConnect Gigabit VPN Firewall automatically performs ―DNS relay‖; i.e.,

because the device itself is not a DNS server, it forwards domain name lookup

requests from the LAN PCs to a DNS server at the ISP. It then relays the DNS

server’s response to the PC.

1 2 ... 39 40 41 42 43 44 45 46 47 48 49 ... 155 156

Pas de commentaire

HP OfficeConnect Firewall Series Manuel d'utilisateur Page 44