# Feature Spotlight: What Massive's ISP Proxies Actually Give You

Massive's ISP proxies are rotating US proxies on AT&T infrastructure, with 10 Gbps connectivity and sticky sessions that hold the same IP until you change the session ID. They sit between datacenter and residential. They typically run steadier than a real consumer device, and their IPs are registered to an ISP rather than a cloud host. This spotlight covers what they do, the limits you should know before building on them, and how they compare with Massive's residential network.

> **Key Takeaways**
>
> - Massive ISP proxies run on AT&T infrastructure in the US, at 10 Gbps, over HTTP, HTTPS, and SOCKS5 ([Massive Docs](https://docs.joinmassive.com/isp-proxies/introduction)).
> - Sticky sessions have no fixed expiry. Reuse a session ID and you keep the same IP. Leave it out and the IP rotates automatically.
> - There's no geotargeting yet, and only ports 80 and 443 are reachable. Use residential when you need a specific country, region, city, or ZIP code.

## What are ISP proxies, and why do teams use them?

ISP proxies are IP addresses registered to an internet service provider but served from infrastructure built for speed. Teams typically reach for them where they would otherwise use datacenter IPs: high-volume jobs that need speed and stable addresses, without the cloud-provider label.

The appeal is simple. Many sites treat cloud-hosted IP ranges with suspicion, because a large share of automated traffic comes from them. In its 2025 Radar Year in Review, Cloudflare reported that Amazon Web Services and Google Cloud originated a quarter of global bot traffic on its network ([Cloudflare](https://blog.cloudflare.com/radar-2025-year-in-review/), 2025). We covered what that means for agents in [why AI agents get blocked on datacenter IPs](https://www.joinmassive.com/blog/why-ai-agents-get-blocked-on-datacenter-ips-and-how-to-fix-it). An IP that belongs to an ISP doesn't sit in those cloud ranges. And unlike a residential device, it isn't somebody's phone that might go offline when they walk into an elevator. The tradeoff: you give up the geographic spread and device variety of a residential network, and you get consistency in return.

## What does Massive's ISP network include?

Per the [ISP Proxies introduction](https://docs.joinmassive.com/isp-proxies/introduction), Massive's ISP network runs on AT&T infrastructure with US coverage, 10 Gbps speeds, and automatic IP rotation. It supports HTTP, HTTPS, and SOCKS5.

The connection details:

| Setting | Value |
|---------|-------|
| Hostname | `isp.joinmassive.com` |
| HTTP port | 8000 |
| HTTPS port | 4080 |
| SOCKS5 port | 8000 (same port as HTTP) |
| Authentication | `{PROXY_USERNAME}:{API_KEY}`, the same pattern as residential |
| Coverage | United States |

With your proxy username and API key exported as `PROXY_USER` and `API_KEY`, a first request looks like this:

```bash title=isp-check.sh
curl ip-api.com \
  -x isp.joinmassive.com:8000 \
  -U "$PROXY_USER:$API_KEY"
```

Run it twice and you'll typically see two different IPs, because requests without a session ID rotate.

## How do sticky sessions work on ISP proxies?

Add `-session-{ID}` to your username, and every request with that ID goes out through the same IP. The ID can be any string up to 255 characters. According to the [ISP sticky sessions docs](https://docs.joinmassive.com/isp-proxies/sticky-sessions), "Sessions continue indefinitely unless the session identifier is changed."

```bash title=isp-sticky.sh
U="$PROXY_USER-session-37"
curl ip-api.com \
  -x isp.joinmassive.com:8000 \
  -U "$U:$API_KEY"
```

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That "indefinitely" is the headline feature, and it's a different model from residential. On Massive's residential network, sessions use a fixed TTL: 15 minutes by default, adjustable from 1 to 1,440 minutes, and not extended by later requests ([Residential sticky sessions](https://docs.joinmassive.com/residential/sticky-sessions)). A residential session is tied to a real device that can go offline. An ISP session isn't, so it can simply keep going.

That makes ISP proxies a natural fit for work where the IP needs to stay put: a multi-step checkout test, a long-running monitoring job against one site, or any flow where a mid-task IP change would reset state.

In Python, the same session looks like this:

```python title=isp_sticky.py
import os
import requests

user = os.environ["PROXY_USER"]
user += "-session-37"
key = os.environ["API_KEY"]
host = "isp.joinmassive.com"
port = 8000
url = "http://ip-api.com/json"

proxy = (
    f"http://{user}:{key}"
    f"@{host}:{port}"
)
proxies = {
    "http": proxy,
    "https": proxy,
}

for _ in range(3):
    r = requests.get(
        url,
        proxies=proxies,
        timeout=30,
    )
    # same IP each time
    print(r.json()["query"])
```

Change `37` to a new value when you want a fresh IP for the next task.

## The limits of Massive's ISP proxies

The constraints are specific, and it's better to know them before you build. Per the [ISP usage restrictions](https://docs.joinmassive.com/isp-proxies/usage-restrictions):

- **Ports 80 and 443 only.** Other ports return `453 Port Forbidden`.
- **UDP is restricted by default.** Contact support if you need it.
- **Port 25 is closed.** No outbound email.
- **Restricted content is blocked.** Requests that break content policy return `452 Disallowed Content`. Legitimate users who need restricted categories can complete KYC with support.
- **No geotargeting (yet).** The [ISP geotargeting page](https://docs.joinmassive.com/isp-proxies/geotargeting) says plainly: "We do not support geo-targeting for ISP proxies yet."

That last point is the one that decides most choices. If your job depends on seeing a page as a user in Munich or Osaka would, ISP proxies aren't the tool.

## ISP or residential: which should you use?

Pick ISP proxies for US workloads that need throughput and long, stable sessions. Pick residential when you need location precision or the variety of real consumer devices. Massive's residential network spans more than 1,000,000 opted-in devices in 195+ countries ([Residential introduction](https://docs.joinmassive.com/residential/introduction)), with [targeting](https://docs.joinmassive.com/residential/geotargeting) by country, subdivision, city, or ZIP code.

| Feature | ISP Proxies | Residential Proxies |
|---|-------------|---------------------|
| Source | AT&T ISP infrastructure | Real consumer devices, opted in via the Massive SDK |
| Coverage | US only | 195+ countries |
| Geotargeting | Not supported yet | Country, subdivision, city, ZIP |
| Sticky sessions | No expiry until the session ID changes | Fixed TTL, 15 min default, up to 24 hours |
| Speed | 10 Gbps | Varies with the device |
| Best for | High-throughput, session-stable US work | Geo-specific data, sites that expect real users |

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You don't have to pick one. You can route US bulk jobs through ISP and send anything location-specific to residential. Both use the same `{PROXY_USERNAME}:{API_KEY}` credentials, so the client code stays the same. What changes is the endpoint (`isp.joinmassive.com` on 8000/4080 versus `network.joinmassive.com` on 65534/65535) and the username parameters: residential sessions can add `-sessionttl-{minutes}` and a session mode, plus geo keys like `-country-US`. For more on splitting traffic this way, see [the multi-provider proxy strategy](https://www.joinmassive.com/blog/multi-provider-proxy-strategy) and [residential vs. datacenter proxies for AI agents](https://www.joinmassive.com/blog/residential-vs-datacenter-proxies-for-ai-agents).

## How do I get started with ISP proxies?

Getting a first request through takes three steps:

1. **Pick your port.** Point your client at `isp.joinmassive.com` on 8000 (HTTP or SOCKS5) or 4080 (HTTPS), per the [ISP authentication docs](https://docs.joinmassive.com/isp-proxies/authentication).
2. **Run the curl check** above with your username and API key, and confirm the IP changes between requests.
3. **Add `-session-{ID}`** only to the steps that need a stable IP.

The docs include ready-made samples for [Python](https://docs.joinmassive.com/isp-proxies/samples/python), [Scrapy](https://docs.joinmassive.com/isp-proxies/samples/scrapy), [Puppeteer](https://docs.joinmassive.com/isp-proxies/samples/puppeteer), [Ruby](https://docs.joinmassive.com/isp-proxies/samples/ruby), and [.NET](https://docs.joinmassive.com/isp-proxies/samples/.net), and the full list of error codes is on the [ISP error types](https://docs.joinmassive.com/isp-proxies/error-types) page. For why device count matters more than IP count on the residential side, see [why more IPs doesn't mean a better proxy network](https://www.joinmassive.com/blog/myth-more-ips-better-proxy-network).

## Frequently Asked Questions

### Where are Massive's ISP proxies located?

In the United States, on AT&T infrastructure. Massive's docs state that geotargeting isn't supported on ISP proxies, so you can't choose a state or city. For location-specific requests, use Massive's residential network, which covers 195+ countries down to the city.

### How long does an ISP sticky session last?

Until you change the session ID. The ISP sticky sessions docs say sessions "continue indefinitely unless the session identifier is changed." Residential sessions, by contrast, use a fixed TTL of 15 minutes by default, adjustable up to 1,440 minutes.

### Which protocols and ports do ISP proxies support?

HTTP on port 8000, HTTPS on port 4080, and SOCKS5 on port 8000, all at isp.joinmassive.com. Outbound traffic can only reach ports 80 and 443. Blocked ports return a 453 error, and UDP is restricted by default.

### How do I authenticate to ISP proxies?

Authentication follows the same `{PROXY_USERNAME}:{API_KEY}` pattern as Massive's residential proxies. Add `-session-{ID}` to the username to keep the same IP across requests.

## ISP proxies: the bottom line

- AT&T-backed, US-only, 10 Gbps, HTTP/HTTPS/SOCKS5.
- Sticky sessions hold the same IP until you change the session ID.
- Only ports 80 and 443 are reachable, and there's no geotargeting, so anything that depends on location belongs on residential.
- Use ISP for steady US throughput.

## Sources

- Massive Docs, ["ISP Proxies introduction"](https://docs.joinmassive.com/isp-proxies/introduction)
- Massive Docs, ["ISP sticky sessions"](https://docs.joinmassive.com/isp-proxies/sticky-sessions)
- Massive Docs, ["ISP usage restrictions"](https://docs.joinmassive.com/isp-proxies/usage-restrictions)
- Massive Docs, ["ISP geotargeting"](https://docs.joinmassive.com/isp-proxies/geotargeting)
- Massive Docs, ["Residential introduction"](https://docs.joinmassive.com/residential/introduction)
- Massive Docs, ["Residential geotargeting"](https://docs.joinmassive.com/residential/geotargeting)
- Massive Docs, ["Residential sticky sessions"](https://docs.joinmassive.com/residential/sticky-sessions)
- Cloudflare, ["The 2025 Cloudflare Radar Year in Review"](https://blog.cloudflare.com/radar-2025-year-in-review/)