Proxy Server

What is a Proxy Server?

A proxy server sits between a user's device and the internet. When a user sends a request, the proxy forwards it to the target server, receives the response, and relays it back. This makes the target server see the proxy's IP address rather than the user's. Proxies come in many flavors: forward proxies act on behalf of clients, reverse proxies sit in front of web servers, and transparent proxies intercept traffic without the user's explicit configuration.

Types of Proxies

• Residential proxies route traffic through IP addresses assigned by ISPs to home users, making them hard to distinguish from genuine visitors.
• Datacenter proxies use IPs from cloud hosting providers and are faster but easier to detect.
• SOCKS proxies operate at a lower network level and support any protocol, not just HTTP.
• Backconnect proxies rotate IP addresses automatically on each request.

Why Proxy Detection Matters

Proxies are essential tools in the arsenal of bot operators and fraudsters. They enable web scraping at scale, credential stuffing campaigns, and multi-accounting on platforms with geographic or per-user restrictions. Identifying proxy traffic is a critical first step in any threat-mitigation strategy.

Detecting Proxies with AntiProxies

AntiProxies classifies incoming IP addresses by connection type, identifying residential proxies, datacenter proxies, VPNs, and Tor exits in real time. By combining IP reputation data with behavioral signals, AntiProxies gives your application the context it needs to distinguish between a privacy-conscious user and an automated threat. See our VPN and proxy detection page for implementation details.

Forward proxies, reverse proxies, and VPNs

The word “proxy” covers several different roles. A forward proxy acts for the client: it sends a request to a site so that the site sees the proxy’s address. A reverse proxy acts for the origin server: it accepts traffic before it reaches an application, commonly for TLS termination, caching, or load balancing. Reverse proxies such as a CDN are normal parts of web infrastructure and should not be treated as evasive traffic.

A VPN also forwards traffic through another network, but it generally encrypts a device-level tunnel and may carry many applications at once. A proxy can be as narrow as one browser setting or as broad as a network gateway. For fraud prevention, the important question is usually not the label but whether the source address is shared, rotating, anonymizing, or inconsistent with the user’s expected context.

A real-world proxy example

Consider a promotion limited to one account per household. An attacker creates 200 accounts through a rotating proxy service. A naive rule that blocks a single IP after five signups will barely slow the campaign because the IP can change on every request. The platform can instead combine a network classification with other evidence:

signup risk = proxy_or_vpn + new_device + repeated_promo_code + rapid_account_creation
if signup risk is high:
require verification or hold the reward for review

This is not a claim that all proxy users are malicious. It is a way to avoid making a high-value decision from one ambiguous signal. A corporate user behind a shared network may be legitimate; the same user plus repeated account creation and a disposable email address deserves more scrutiny.

How proxy traffic is detected

Detection providers maintain and validate IP ranges associated with hosting companies, commercial VPNs, Tor exits, open proxies, and proxy networks. Network ownership and routing data can reveal that an address belongs to a datacenter; active research and observed behavior can identify a proxy service within that range. This information is most useful when it is refreshed regularly because providers add, remove, and reassign addresses.

Network intelligence does have limits. Residential proxies may use real household IP addresses, and a legitimate user can connect from a corporate proxy. Combine classification with session behavior, device signals, and the sensitivity of the action before applying a block.

Common misconceptions

“A proxy is always anonymous.” Many proxies forward identifying headers, keep logs, or are operated by an employer or network provider. The destination may still have enough context to assess the request.

“Every shared IP is a proxy.” Mobile carriers, offices, hotels, and carrier-grade NAT can make many legitimate people appear behind one public IP. Shared use alone is not proof of proxying.

“IP blocking is the only response.” Rate limits, step-up verification, and action-specific rules often reduce abuse with fewer false positives than a permanent network-wide ban.

FAQ

Are reverse proxies bad for SEO or security?

No. A reverse proxy is a normal way to protect and scale a website. The application must be configured to trust forwarded client-IP headers only from known proxy infrastructure, otherwise attackers can spoof them.

Why do attackers use proxies?

They distribute requests, change apparent location, and evade per-IP controls. Learn how this affects fraud workflows in our article on proxies and KYC bypass attempts.