Cloudflare, Inc.

Cloudfare, Inc.

Srikanth N Rao

Matthew Browning Prince

Lee Hahn Holloway

Ian Gerald Pye

Matthieu Philippe François Tourne

Ray Raymond Bejjani

Terry Paul Rodery, Jr

An authoritative domain name system (DNS) server receives DNS requests for domains. The authoritative DNS server transmits DNS responses to the DNS requests with address records that include IP addresses that are selected from a larger pool of IP addresses, where a first DNS response can include IP addresses different from IP addresses included in a second DNS response for the same domain. Also, the same IP addresses may be returned for a first domain and a different, second domain. The authoritative DNS server may select the IP addresses to include in DNS responses to the DNS requests using a round-robin process.

Authoritative domain name system (DNS) server responding to DNS requests with IP addresses selected from a larger pool of IP addresses

An authoritative DNS server receives DNS requests for domains. The authoritative DNS server responds to the requests with address records that include IP addresses that are selected from a larger pool of IP addresses, where a first response to a DNS query for a domain can include IP addresses different from IP addresses included in a second response for the same domain. Also, the same IP addresses may be returned for a first domain and a different, second domain. The authoritative DNS server may randomly select the IP addresses to include in responses to the requests regardless of the domain.

An attack is detected on a first IP address and a determination is made that the first IP address is associated with a primary digital certificate that is bound with multiple different domains. For each of these domains, a secondary certificate is accessed that is bound only to that domain and that secondary certificate is associated with a unique IP address such that each of the different domains has a unique IP address associated with its secondary certificate respectively. The attack is isolated to the domain the attack follows.

Detecting and isolating an attack directed at an IP address associated with a digital certificate bound with multiple domains

A cloud-based proxy service identifies a denial-of-service (DoS) attack including determining that there is a potential DoS attack being directed to an IP address of the cloud-based proxy service; and responsive to determining that there are a plurality of domains that resolve to that IP address, identifying the one of the plurality of domains that is the target of the DoS attack. The domain that is under attack is identified by scattering the plurality of domains to resolve to different IP addresses, where a result of the scattering is that each of those domains resolves to a different IP address, and identifying one of those plurality of domains as the target of the DoS attack by determining that there is an abnormally high amount of traffic being directed to the IP address in which that domain resolves.

Identifying a denial-of-service attack in a cloud-based proxy service

A proxy server in a cloud-based proxy service receives a secure session request from a client device as a result of a Domain Name System (DNS) request for a domain resolving to the proxy server. The proxy server participates in a secure session negotiation with the client device including transmitting a digital certificate to the client device that is bound to domain and multiple other domains. The proxy server receives an encrypted request from the client device for an action to be performed on a resource that is hosted at an origin server corresponding to the domain. The proxy server decrypts the request and participates in a secure session negotiation with the origin server including receiving a digital certificate from the origin server. The proxy server encrypts the decrypted request using the digital certificate from the origin server and transmits the encrypted request to the origin server.

Supporting secure sessions in a cloud-based proxy service

Message(s) are received from each one of multiple proxy servers, which are anycasted to the same IP address, that indicate source IP addresses of packets that are received that are directed to that same IP address. These proxy servers receive the packets as result of domain(s) resolving to that same IP address, and a particular one of the proxy servers receives the packets as a result of an anycast protocol implementation selecting that proxy server. Based on these message(s) from each of the proxy servers, a determination of the likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers is determined. A message is transmitted to each of the proxy servers that indicates which source IP addresses of packets are not likely to be legitimately received at that proxy server.

Determining the likelihood of traffic being legitimately received at a proxy server in a cloud-based proxy service

A proxy server in a cloud-based proxy service receives a message that indicates that a domain, whose traffic passes through the proxy server, may be under a denial-of-service (DoS) attack. The proxy server enables a rule for the domain that specifies that future requests for resources at that domain are subject to at least initially passing a set of one or more challenges. In response to receiving a request for a resource of that domain from a visitor, the proxy server presents the set of challenges that, if not passed, are an indication that that the visitor is part of the DoS attack. If the set of challenges are passed, the request may be processed. If the set of challenges are not passed, the request may be dropped.

Mitigating a denial-of-service attack in a cloud-based proxy service

A proxy server in a cloud-based proxy service receives a secure session request from a client device for a secure session. The secure session request is received at the proxy server as a result of a Domain Name System (DNS) request for a domain resolving to the proxy server. The proxy server participates in a secure session negotiation with the client device including transmitting a digital certificate to the client device that is bound to domain and multiple other domains. The proxy server receives an encrypted request from the client device for an action to be performed on a resource that is hosted at an origin server corresponding to the domain. The proxy server decrypts the request and participates in a secure session negotiation with the origin server including receiving a digital certificate from the origin server. The proxy server encrypts the decrypted request using the digital certificate from the origin server and transmits the encrypted request to the origin server.

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San Francisco, CA, United States of America

Srikanth N Rao