    def __init__(
        self,
        reactor: IReactorCore,
        tls_client_options_factory: Optional[FederationPolicyForHTTPS],
        user_agent: bytes,
        ip_blacklist: IPSet,
        _srv_resolver: Optional[SrvResolver] = None,
        _well_known_resolver: Optional[WellKnownResolver] = None,
A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks.