R3204P16-HP Load Balancing Module Network Management Configuration Guide-6PW101
Table Of Contents
- Title page
- Contents
- Interface management configuration
- IP addressing configuration
- MAC address table configuration
- Layer 2 forwarding configuration
- Layer 2 forwarding overview
- Configuring general Layer 2 forwarding
- Configuring inline Layer 2 forwarding
- Configuring inter-VLAN Layer 2 forwarding
- Forward-type inline Layer 2 forwarding configuration example
- Blackhole-type inline Layer 2 forwarding configuration example
- Inter-VLAN Layer 2 forwarding configuration example
- VLAN configuration
- ARP configuration
- Gratuitous ARP configuration
- Proxy ARP configuration
- Layer 3 forwarding configuration
- NAT configuration
- Overview
- Configuring a NAT policy in the web interface
- Configuring NAT in the CLIs
- Configuration guidelines
- ALG configuration
- Static route configuration
- RIP configuration
- OSPF configuration
- BGP configuration
- Policy-based routing configuration
- Route displaying
- DNS configuration
- Overview
- Configuring DNS on the web interface
- Configuring DNS in the CLIs
- Troubleshooting IPv4 DNS configuration
- Support and other resources
- Index
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The DNS proxy simplifies network management. When the DNS server address is changed, you only
need to change the configuration on the DNS proxy instead of on each DNS client.
Figure 110 DNS proxy networking application
Operation of a DNS proxy
1. A DNS client considers the DNS proxy as the DNS server, and sends a DNS request to the DNS
proxy, that is, the destination address of the request is the IP address of the DNS proxy.
2. The DNS proxy searches the local static domain name resolution table after receiving the request.
If the requested information exists in the table, the DNS proxy returns a DNS reply to the client.
3. If the requested information does not exist in the static domain name resolution table, the DNS
proxy sends the request to the designated DNS server for domain name resolution.
4. After receiving a reply from the DNS server, the DNS proxy forwards the reply to the DNS client.
DNS spoofing
With DNS proxy enabled but no DNS server or route to the DNS server specified, an LB module cannot
forward a DNS request, or answer a request. You can enable DNS spoofing on the LB module to spoof
a reply with the configured IP address. Once a DNS server is reachable, the LB module will send DHCP
requests to the server and return the replies to the requesting DNS clients.
Configuring DNS on the web interface
Configuration overview
DNS provides three functions, static name resolution, dynamic domain name resolution, and DNS proxy.
• Static name resolution: Name resolution is carried out through manually configured name
resolution entries.
• Dynamic name resolution: A LB module resolves domain names through the DNS server.
• DNS proxy: You can configure a LB module as a DNS proxy.
NOTE:
If both static domain name resolution and dynamic domain name resolution are configured, the LB module
first checks the static name resolution table for an IP address. If no IP address is available, it then contacts
the DNS server for dynamic name resolution.