Exam CISSP topic 1 question 283 discussion

I am going with B, my thinking is that if a disaster happens you update your DNS to point to the backup site, ASN is country specific: "The BGP routing is the best path to get to a specific website. The BGP routing is selected based on the BGP ASN. The BGP ASN is the country-specific number for the Internet. It is the ASN that is used to route traffic into and out of the country. For example, the ASN for the United States is 65515, which is the number that is used to route IP packets to and from the United States. Do I have to pay for an ASN? No. ASN is a non-profit organization that manages the allocation of IP addresses and Autonomous System Numbers (ASNs) to Internet Service Providers (ISPs) and other organizations that connect to the Internet." https://www.wallarm.com/what/bgp-routing-explanation#:~:text=The%20BGP%20ASN%20is%20the,and%20from%20the%20United%20States.

Not C. Usually done by the network provider and propagates in a few minutes to a few hours depending on the network, but faster than global DNS propagation.

Agree with B. Typically 24-48 hours for full global propagation, although some changes may take effect sooner depending on TTL settings.

It is DNS! It is NOT BGP, because what online shop runs his own AS system!? You get resilience by redundance and you have to add your backup system in you DNS records. If you would run your own AS, every online shop has to have its own IP-ranges and so on and so forth, that does not happen in practice.

I will rebel against Chat GPT (saying C as the answer) and go with A.

Updating the Border Gateway Protocol (BGP) autonomous system number involves coordination with internet service providers (ISPs) to update routing information, which can take significant time due to propagation delays across the internet. BGP updates may require coordination with multiple ISPs and can lead to prolonged downtime or service disruption until the updates are fully propagated and the website becomes reachable again.

B takes the longest out of all of them.

"When a domain's nameservers are updated, it can take 24–48 hours for the change to take effect. This period is known as DNS propagation, which is the time it takes for changes to update throughout the web." I think the answer is b. BGP changes takes maximum 120 seconds to update. Unless I missing something with the wording of the question. Just a bizarre question.

What does BGP have to do with the website?

C. Update the Border Gateway Protocol (BGP) autonomous system number. The propagation of BGP updates across the Internet can take time, and it's not uncommon for BGP changes to have a longer duration for full operational recovery.

B. It is a trick question. It would be C if it is true but why would you change BGP ASN during recovery? BGP ASN is used company-wide (within the region) unless the DR site is in another region but that should be already allocated beforehand

BGP (Border Gateway Protocol) is used for routing between different autonomous systems on the internet. Changing the BGP autonomous system number involves coordination with Internet Service Providers (ISPs) and may require time for the changes to propagate across the internet. BGP updates can take time to be disseminated to other routers on the internet, and the full convergence of the BGP routing tables across the network can take a significant amount of time.

Option B: DNS record changes involve propagating globally through registrars and caching DNS servers. This fundamental availability step will take the most time. -Updating NAT tables, BGP info, and network adapters are all crucial recovery tasks but can be completed more rapidly without relying on external registration and DNS refresh delays. Since DNS underpins overall access and availability, any delays in updating DNS server addresses will directly extend total recovery time. This makes option B the step most likely to have the longest duration before service restoration.

BGP and DNS depend on the location the request is coming from, which also makes it equally hard to measure. However BGP is typically in minutes versus DNS: DNS propagation is the time frame it takes for DNS changes to be updated across the Internet. A change to a DNS record—for example, changing the IP address defined for a specific hostname—can take up to 72 hours to propagate worldwide, although it typically takes a few hours.

Yes, it is possible that the DNS update may take only a few minutes to propagate, but it can also take up to 48 hours or more in some cases. However, if we consider the specific scenario described in the question, where the retail website is the only source of revenue for the organization, it is likely that they have already implemented a robust DNS infrastructure with fast propagation times and low TTL values. In this case, updating the Border Gateway Protocol (BGP) autonomous system number (ASN) would likely take the most time, as it requires coordination with ISPs and can take several hours to propagate throughout the Internet. Therefore, the correct answer would be C - Update the Border Gateway Protocol (BGP) autonomous system number.

They always say that 24-48 hour range in books, but from my experience, dns typically take minutes to take effect. Since it's in the books though, it's probably still the best answer.

Note that DNS record changes may take 24-48 hours to take effect. This period is called DNS propagation.