CGNAT (Carrier-Grade NAT) is a large-scale network address translation system used by ISPs and mobile carriers to share a limited pool of public IPv4 addresses among thousands of subscribers. It adds a second NAT layer beyond the customer router.
In a CGNAT setup, your home router assigns private IPs to your devices (first NAT layer), and your ISP maps your router private IP to a shared public IP (second NAT layer). Thousands of subscribers may share the same public IP. The ISP uses port ranges to distinguish traffic from different customers. Mobile carriers rely heavily on CGNAT because their subscriber count far exceeds available IPv4 addresses.
This is largely a plan and configuration choice, not a technical limitation.
USER-cgnat-session-task01Everything lives in the username -- add "cgnat" to any proxy credential to apply cgnat to a single task. Swap "task01" for a new label to spin up an independent, isolated identity.
KnoxProxy sticky sessions persist up to 30 minutes on residential (60 on mobile), and the window refreshes with activity.
Each session or connection label gets its own exit, so parallel identities never collide.
This costs nothing beyond bandwidth -- successful responses are billed, not the session or connection itself.
Run as many parallel sessions or connections as the job needs -- concurrency is not capped on any plan.
A mobile carrier assigns 5,000 subscribers in a city to 50 shared public IPs using CGNAT, meaning each public IP represents about 100 real mobile users.
CGNAT is why mobile proxy IPs are so trusted. Blocking a CGNAT IP would affect thousands of legitimate users, so websites almost never block mobile carrier IPs.
CGNAT itself adds minimal latency. However, the shared nature of CGNAT IPs means other users on the same IP can affect its reputation. This is rarely an issue because the sheer volume of real users keeps the IP reputation high.
Generally no. CGNAT exists specifically because the carrier does not have enough IPs to assign one per subscriber. Some business mobile plans offer dedicated IPs, but they cost more.
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