What are XEvil proxies?

XEvil proxies are proxies you load into XEvil, the captcha-solving software, so it can solve large volumes of Google ReCaptcha without every request coming from your own IP. In practice they are IPv6 proxies, because Google's ReCaptcha supports IPv6 and the IPv6 address space is enormous — which makes them fast and cheap for this one job.

How XEvil proxies work

The service we recommend uses a two-step setup, which is worth understanding:

1. Front-end proxies. You're given a small list of static IPv6 proxy addresses. These stay constant and are your access point into the proxy network.
2. Rotating tunnel. Behind those front-end proxies sits a large pool. Each connection you make is assigned a fresh IP from that pool, so while you always connect to the same front-end addresses, the websites XEvil hits see a different IP almost every time.

That rotation is what keeps Google from flagging the pattern. To XEvil it looks like one stable proxy list; to Google it looks like thousands of different visitors.

Why IPv6 and not IPv4?

Two reasons. First, Google's ReCaptcha supports IPv6, so the proxies work for the exact target XEvil cares about. Second, IPv6 has a vast address space, so providers can offer big rotating pools cheaply — the entry package starts at $15/month. The trade-off is that IPv6 proxies only work on sites that support IPv6, which is why you don't use them for the posting itself.

What they're used with

XEvil is the captcha engine behind a lot of automated link building — it plugs into XRumer, GSA Search Engine Ranker and similar tools. Whenever those tools hit a Google ReCaptcha, XEvil solves it, and the IPv6 proxies keep that solving anonymous and unblocked.

Next: why XEvil needs proxies at all →