Advanced Onion Router is a portable Windows client for directing application connections through the onion-routing network. Also known as AdvOR, it combines a local proxy with controls for intercepting programs, selecting network circuits and changing connection identities. Its interface exposes routing decisions that would otherwise require separate proxy and configuration tools.
Process interception
Advanced Onion Router can redirect connections from a selected program even when that program has no proxy settings of its own. A point-and-click process selector chooses the application to intercept. The interceptor can also reject unsupported protocols and replace information the program receives about the local computer, including its hostname and system time.
Interception extends to child processes launched by an intercepted application. A favorite-process list starts chosen programs and intercepts them when AdvOR starts. The interceptor cannot attach to 64-bit processes, which limits the applications that can use this method of redirection.
Proxy connections
Applications that already support a proxy can send their connections to AdvOR’s local listening port. That port accepts SOCKS4, SOCKS5, HTTP and HTTPS proxy protocols and detects which protocol the application uses. Different supported clients can therefore use the same port without a separate listener for each protocol.
Advanced Onion Router also supports proxy chains and NTLM-authenticated corporate proxies. These controls address the connection between the computer and its upstream proxy infrastructure, while circuit selection controls the route within the onion-routing network.
Circuit Builder
The circuit builder accepts a list of nodes for constructing a route. Existing circuits and router-selection dialogs provide controls for adding routers to favorites or banning them from selection. Circuit length is configurable from one to ten routers, and the OR network page lets users change circuit priorities.
Route restrictions can also work at the country and network-operator levels. Advanced Onion Router can avoid placing routers from the same country in a circuit. It can estimate autonomous-system paths—the networks expected to carry traffic between points—and exclude circuits whose estimated paths intersect. This selection uses estimates rather than a verified map of every connection’s physical route.
Identity changes
AdvOR supports automatic IP and identity changes with a configurable algorithm for selecting exit routers. Identity handling also reaches beyond the circuit itself: its HTTP header filter creates replacement browser headers associated with an identity and generates new values when that identity changes.
The identity-isolation controls combine browser-cookie deletion, expiration of an internal cookie cache and replacement browser identity information. They also include cleanup of Flash and Silverlight cookies. Browser-cookie cleanup is limited to the browsers supported by the program.
Portable configuration
Advanced Onion Router keeps its settings in the application folder and does not write them to the Windows registry. Optional AES encryption protects the saved configuration files. A read-only mode makes no file writes when the application runs from read-only media.
