When managing security measures on Cloudflare, determining which Autonomous System Numbers (ASNs) to never block is crucial for maintaining accessibility and preventing unintended disruptions to legitimate traffic. ASNs represent groups of IP addresses allocated to specific organizations or entities, including internet service providers (ISPs), content delivery networks (CDNs), and cloud computing providers. By identifying ASNs that should always be allowed, website owners can ensure uninterrupted access to essential services, maintain optimal performance, and mitigate the risk of blocking legitimate traffic. Below are several key points to consider when determining which ASNs to never block on Cloudflare:
1. Cloudflare Infrastructure:
One of the most critical ASNs to never block on Cloudflare is Cloudflare's own infrastructure. Cloudflare operates a global network of data centers and edge servers that deliver content, optimize performance, and provide security services for websites and web applications. Blocking Cloudflare's ASN could disrupt traffic routing, impact website availability, and compromise the effectiveness of Cloudflare's services in protecting against security threats and mitigating DDoS attacks.
2. Search Engine Crawlers:
Search engine crawlers, such as Googlebot, Bingbot, and other reputable bots, play a vital role in indexing website content and determining search engine rankings. Blocking ASNs associated with search engine crawlers can prevent these bots from accessing and indexing website content, leading to decreased visibility and ranking in search engine results. Maintaining accessibility for search engine crawlers ensures that websites are properly indexed and ranked, contributing to organic traffic and user engagement.
3. Content Delivery Networks (CDNs):
Many websites leverage CDNs to deliver content more efficiently, improve performance, and enhance user experience. CDNs cache content on edge servers located closer to end-users, reducing latency and speeding up content delivery. Blocking ASNs associated with CDNs could disrupt content delivery, increase loading times, and diminish the benefits of using CDNs to optimize website performance. Allowing access for CDN ASNs ensures seamless content delivery and enhances website performance for users worldwide.
4. Hosting Providers:
Hosting providers host websites and web applications on servers connected to specific ASNs. Blocking ASNs associated with hosting providers could prevent legitimate traffic from accessing hosted websites and disrupt website availability. It's essential to identify and whitelist ASNs used by hosting providers to ensure uninterrupted access to hosted services and prevent unintended disruptions or downtime for websites and web applications.
5. Major Internet Service Providers (ISPs):
Major ISPs provide internet connectivity to users worldwide and route traffic through their networks using specific ASNs. Blocking ASNs associated with major ISPs could result in widespread access issues for users accessing websites and web applications through these ISPs. Allowing access for major ISP ASNs ensures broad accessibility and optimal performance for users regardless of their internet service provider.
6. Web Analytics and Monitoring Services:
Web analytics and monitoring services track website traffic, user behavior, and performance metrics to provide insights into website performance and user engagement. Blocking ASNs associated with web analytics and monitoring services could prevent these services from collecting data, monitoring website performance, and detecting security threats. Allowing access for these ASNs ensures accurate tracking, monitoring, and analysis of website traffic and performance.
7. Payment Processors and Financial Institutions:
Websites that process payments or handle sensitive financial transactions rely on secure connections and infrastructure provided by payment processors and financial institutions. Blocking ASNs associated with payment processors and financial institutions could disrupt payment processing, compromise security, and lead to financial losses or compliance issues. Allowing access for these ASNs ensures secure and reliable payment processing for e-commerce websites and online businesses.
8. Email and Communication Services:
Email and communication services play a crucial role in facilitating communication and engagement with users, customers, and stakeholders. Blocking ASNs associated with email and communication services could prevent emails from being delivered, disrupt communication channels, and impact customer support and marketing efforts. Allowing access for these ASNs ensures reliable email delivery and communication capabilities for websites and online businesses.
9. Regulatory and Government Agencies:
Regulatory and government agencies may access websites for compliance monitoring, law enforcement purposes, or public information dissemination. Blocking ASNs associated with regulatory and government agencies could hinder access to websites by authorized personnel and raise compliance concerns. Allowing access for these ASNs ensures compliance with regulatory requirements and facilitates cooperation with government authorities when necessary.
Examples of ASN to Never Block on Cloudflare:
- Google ASNs (AS15169, AS36040, AS396982)
- Amazon ASNs (AS16509, AS14618)
- Microsoft ASNs (AS8075, AS8068)
- Cloudflare ASNs (AS13335)
- Akamai ASNs (AS16625, AS20940)
- Facebook ASNs (AS32934, AS54115)
- Apple ASNs (AS714, AS6185)
- DigitalOcean ASNs (AS14061)
- Fastly ASNs (AS54113)
- OVH ASNs (AS16276)
I can't provide a more definitive list since it can vary based on your specific needs and the services you use. However, you can find guidance on determining which ASNs to whitelist on Cloudflare based on your requirements and traffic patterns.
In summary, determining which ASNs to never block on Cloudflare is essential for maintaining accessibility, performance, and security for websites and web applications. By identifying and whitelisting critical ASNs, including Cloudflare's infrastructure, search engine crawlers, CDNs, hosting providers, major ISPs, web analytics and monitoring services, payment processors, email and communication services, and regulatory and government agencies, website owners can ensure uninterrupted access to essential services, mitigate the risk of blocking legitimate traffic, and maintain optimal website performance and user experience. Collaboration with security experts and regular monitoring of traffic patterns can help identify and address potential threats while minimizing disruptions to legitimate traffic.