The Houston IP Pool: How Many Addresses One Line Can Reach

A line that rotates without limit sounds like it should give you an endless supply of addresses. It gives you a very large supply, but not an endless one, because every address comes from a pool the carrier runs for the region. Understanding how that pool works lets you plan rotation sensibly instead of being surprised by a repeat. Here is how it works for our Houston rack.

Where an address comes from

When a SIM attaches to the network, the carrier gives it a private address and maps its traffic out through a public one chosen from a block the carrier assigns to that part of the network. For a Houston SIM that block is regional: it serves a large chunk of Texas, not just the rack. The public address you see on a lookup page is drawn from that regional block, which is why it geolocates to Houston or to Texas and never to a street.

When you rotate, the device drops and re-establishes its session, and the carrier hands out a public address again. Usually a different one, because there are many to choose from. Sometimes the same one, because the choice is not made to please you; it is made by the carrier's gateway doing its normal job.

How big the pool really is

We are not going to publish a number, because the carriers do not publish one and we would be guessing. What we can say from watching our own lines is that one Houston SIM, rotated steadily over a month, sees many hundreds of distinct public addresses on each carrier, and that T-Mobile tends to show the most variety, AT&T a close second, and Verizon the least, since Verizon organises its regional pool over a wider area with longer-lived mappings.

The pool is also shared with everyone else in the region. Every public address you receive is simultaneously in use by thousands of other subscribers. That is the point of carrier NAT and the reason the address is trusted, but it means the size of the pool is a property of the carrier's Texas network, not of your line.

Why repeats happen and why they are fine

If you rotate ten times you may see one address twice. The gateway reuses addresses freely, and a block that serves a region is not shuffled to avoid giving a SIM the same one again. For almost every job this is harmless. A site that sees a Houston carrier address today and the same one next Tuesday sees exactly what it sees from any real Houston phone.

The only job where a repeat matters is a strict rule like never hit this endpoint twice from the same address. If that is your requirement, keep a short list of addresses you have used and rotate again when you get a repeat. It costs a second and there is no wait between rotations.

• Addresses are picked by the carrier gateway from a regional block
• One SIM sees many hundreds of distinct addresses over a month of rotating
• Repeats are normal carrier behaviour and harmless for most work
• Strict no-repeat jobs: keep a used list and rotate on a hit

Sticky sessions and pool pressure

Between rotations the address holds for as long as the carrier keeps the session alive. In quiet hours that can be most of a day; in busy periods the gateway recycles mappings sooner. You will notice that an address held overnight will sometimes change by morning without you asking. That is pool pressure, the gateway reclaiming mappings, and it is the same thing a phone experiences.

If a job needs the address to hold, use Verizon, which keeps sessions longest in our experience, and avoid rotating by hand. If a job needs variety, use T-Mobile and rotate on a timer. AT&T sits comfortably between the two.

Getting more distinct addresses

The way to reach more addresses is not to rotate one line faster. It is to run more lines, ideally across carriers, since each carrier has its own regional pool and the three pools do not overlap. Three lines, one per carrier, give you three independent pools from the same Houston rack. Five or six lines across carriers, each rotating on a timer, cover a large research job comfortably without ever needing to think about repeats.

A practical rotation plan

For logged-in account work: do not rotate during a session; let the carrier hold the address. For monitoring Texas pages at intervals: rotate on a timer every fifteen to thirty minutes, which keeps the address fresh without churning through the pool for no reason. For bursty research: rotate every few hundred requests and keep a used list if repeats matter. In all cases rotation is unlimited, there is no waiting period, and you can trigger it from the dashboard, a rotation link, the API or a timer.

Frequently asked