Workflow
The transparent DNS proxy is implemented by changing the destination IP address of DNS requests.
Figure 57: Transparent DNS proxy workflow
Table 13: Workflow description
Step | Source IP address | Destination IP address |
|---|---|---|
1. An intranet user on the client host sends a DNS request to the LB device. | Host IP address | IP address of DNS server A |
2. The LB device selects a DNS server to forward the DNS request according to the scheduling algorithm. | N/A | N/A |
3. The LB device changes the destination IP address of the DNS request as the IP address of the selected DNS server. |
| IP address of the selected DNS server |
4. The DNS server processes the DNS request and replies with a DNS response. | IP address of the selected DNS server | Host IP address |
5. The LB device changes the source IP address of the DNS response as the destination IP address of the DNS request. | IP address of DNS server A | Host IP address |
6. The intranet user accesses the external server according to the resolved IP address in the DNS response. | Host IP address | IP address of the external server |
7. The external server responds to the intranet user. | IP address of the external server | Host IP address |