Guides & explainers
In-depth guides on IP, WebRTC, DNS, proxy routing, and the regional quirks of the major services we test.
How to tell the IP class of every service you use, using IPCombo's per-target column
Single-IP echo sites collapse everything to one number. IPCombo's per-target column gives you a different source IP per destination. Here is the four-step process to read that column and figure out which class each service is actually using.
The ultimate proxy selection guide: a decision tree by use case, region, ASN, and price
Most proxy-selection mistakes come from optimizing the wrong axis. Start with what you need to do, then pick the class, region, and ASN. Here is the decision tree we use internally at IPCombo, with no brand names attached.
ChatGPT deep review: GPT-5 reasoning, Codex IDE, Sora, Plus vs Pro, and region limits
GPT-5 isn't one model — it's a router over a reasoning layer. This review covers how the routing works, what Codex and Sora inherit from it, the real difference between Plus and Pro, and how to test whether your current IP can use full reasoning.
WebRTC leaks, explained: what your browser is leaking and how to stop it
WebRTC negotiates peer-to-peer connections by gathering local and reflexive IP addresses. When you use a proxy, those candidates can reveal your real IP. Here's how the leak happens, what each candidate type means, and what actually fixes it.
Why IPCombo uses cdn-cgi/trace to get per-target exit IPs
Most IP-checking sites show you a single public IP. That's your proxy exit, but it doesn't tell you which proxy rule actually fired for each destination. cdn-cgi/trace, Cloudflare's diagnostic endpoint, gives us per-target proof of routing.
How to pick the right proxy region for each service
Not every service wants the same proxy region. ChatGPT wants US or JP. Bilibili wants CN. Stripe wants wherever your business is registered. Here's the decision tree we use internally.
Datacenter vs residential vs mobile IPs: which one to use
All proxy IPs are not equal. Datacenter IPs are fast and cheap but blacklisted by every major streaming service. Residential IPs are slower but pass. Mobile IPs are the gold standard for the hardest services. Here's when to use each.
How to read the IPCombo diagnosis card
After a full test, IPCombo shows a one-line health score plus a list of findings. The score isn't a vanity metric — it directly reflects what's wrong and how to fix it. Here's how to read it.