How to Eliminate DNS Lookups for Faster Mobile App HTTP Requests

Background

In the wireless era, network stability is poor and app traffic is sensitive; each HTTP request between the app and server requires DNS resolution, which can be a bottleneck.

1. HTTP request flow in the PC era

1. Browser or PC client queries DNS server to obtain the IP (usually an Nginx IP).

2. The client uses the IP to access Nginx.

3. Nginx forwards the request to the actual web server that handles the HTTP request.

2. Characteristics of the wireless app era

(1) DNS resolution time cannot be ignored.

(2) If DNS is hijacked, the entire app fails.

3. DNS‑free HTTP request optimization scheme

(1) On the first access, the client fetches a list of server IPs and stores it locally; subsequent accesses follow the normal HTTP flow.

(2) On later accesses, the client directly uses the stored IP list, eliminating DNS queries.

(3) If DNS is hijacked, the client can still try the IPs from the list.

4. Potential issues and solutions

(1) Load balancing without DNS: the app randomly selects an IP from the list.

(2) Horizontal scaling without Nginx: simply add new IPs to the list.

(3) Reducing traffic from repeatedly fetching the IP list: add a version number; the client only re‑downloads the list when the version changes.

(4) Supporting heterogeneous servers: include a weight with each IP (e.g., 192.168.1.1,10; 192.168.1.2,10; 192.168.1.3,20) so the app can balance load according to server capacity.

5. Summary of benefits

• No DNS lookup per request, saving time.

• No Nginx forwarding per request, saving time.

• No repeated IP‑list download, saving bandwidth.

• Resilience to DNS hijacking by using local IPs.