DNS Literacy Series 4: Follow domain name migration

DNS Literacy Series 4: Pay attention to the more common domain name migration, domain name migration is to modify the authoritative DNS of the domain name, the original authoritative DNS of the domain name ABC. COM will be migrated from A to B. In practice, the most common form is to transfer the domain name to another DNS service provider for resolution. This article discusses several important issues during domain name migration. Www.2cto.com 1. Why is domain name migration required? Under normal circumstances, the domain name we purchased from there will be resolved by the DNS as the authoritative DNS of the domain name. If you are not satisfied with their service quality or they cannot provide the service content you need, you need to migrate the domain name to the DNS you think is better. 2. Correct domain name Migration Process: 1. First, add your domain name to B, including SOA, NS, A, CNAME, and MX records. Then, use tools such as dig/nslookup to verify whether the added record has taken effect. For example, verify A record WWW. ABC. COM: dig @ B WWW. ABC. COM A2. go to the original domain name registrar and change the authoritative DNS of the domain name to B, that is, change the NS record of the domain name to B. Note: Do not delete other records on the domain name's original authoritative DNS for a period of time. Then, verify the modification on the top-level domain DNS of the domain name. For example, ABC. COM authoritative DNS: dig @ a.gtld-servers.net ABC. com ns iii. Transition Period of domain name migration: the domain name resolution right changes when the domain name authoritative DNS is transferred from A to B. Recursive DNS around the world needs to know that this change takes some time, because DNS caches the previous status of the domain name, it takes time to update to the latest status. Www.2cto.com IV. Determination of the transition period: We query the domain name trace to learn the TTL value of the domain name NS record. For example, query the CN Domain Name. # Dig xxx.cn ns + tracexxx.cn. 21600 in ns ns.xxx.cn.xxx.cn. 21600 in ns ns.xxx.com .;; encoded ed 83 bytes from 203.119.25.1 #53 (A.DNS.cn) in 46 msxxx.cn. 21600 in ns ns.xxx.cn.xxx.cn. 21600 in ns ns.xxx.com .;; received 83 bytes from 129.44.79.4 #53 (ns.xxx.cn) in 78 ms the authoritative DNS records the same TTL value as the NS records on top-level domain DNS, the transition period is 21600 seconds. In special cases, if the TTL value of the NS record of the domain name defined on the original authoritative DNS of the domain name is different from the value defined on the top-level domain DNS. In this case, the TTL on the original authoritative DNS is a valid value. For example, 163.cn: # dig 163.cn ns + trace163.cn. 21600 in ns ns1.newfavor.net.163.cn. 21600 in ns ns2.newfavor.net .;; encoded ed 72 bytes from 203.119.28.1 #53 (D.DNS.cn) in 62 ms163.cn. 10800 in ns dns1.amway.com.163.cn. 10800 in ns ns2.newfavor.net.163.cn. 10800 in ns ns1.newfavor.net .;; received 174 bytes from 61.145.126.88 #53 (ns1.newfavor.net) in 93 ms, you can see that the TTL of the NS record for this domain name on the top-level domain is 21600, And the authoritative DNS redefines it as 10800, at this time, the original authoritative DNS The TTL on is a valid value. In practice, we take the larger value of the two as the final reference value. The following lists the TTL values of several domain name NS records: COM. TTL = 172800 (48 hours) NET. TTL = 172800 (48 hours) ORG. TTL = 86400 (24 hours) CN. TTL = 21600 (6 hours)