What are the common problems with domain name resolution? Full summary of practical solutions

for website operators and enterprise operation and maintenance personnel, domain name resolution is the core link connecting the domain name and the server. Once there is a problem, it will lead to abnormal website access and affect the normal operation of the business. However, in practice, many practitioners will encounter various domain name resolution related problems, but cannot find targeted solutions. This article will sort out the most common types of problems in the process of domain name resolution, and give feasible solutions based on practical experience to help readers quickly troubleshoot and ensure the stability of domain name services.

What should I do if the domain name resolution delay does not take effect?

domain name resolution effective delay is one of the most common problems, many users after the configuration of the resolution record, delayed access to the website, such problems are usually related to caching or resolution links.

1, the local DNS cache is not refreshed

most devices will cache the old domain name resolution results, even if the user modifies the resolution records in the background of the domain name service provider, the local device will still read the old data in the cache. This can be handled by clearing the local DNS cache. Windows systems can enter ipconfig /flushdns at the command prompt, Mac systems can enter sudo dscacheutil -flushcache at the end point, and then re-test the domain name access after completion.

2, top DNS server cache synchronization is slow

domain name resolution records are modified, it needs to be synced to top-level DNS servers around the world, a process that can take hours or more. If you are in a hurry, you can check whether the domain name service provider provides a "forced refresh" function. Some service providers support manually triggering top-level server synchronization; you can also replace public DNS servers, such as using 114.114.114.114 or 8.8.8.8, which usually update the cache faster.

What are the configuration errors of domain name resolution records?

domain name resolution record configuration error is one of the core causes of access failure. Many users are not familiar with the resolution record type, which is prone to various configuration errors.

1, the record type does not match the requirements

common domain name resolution record types are A records, CNAME records, MX records, etc. Different types correspond to different business scenarios. For example, A records are used to point domain names to IPv4 addresses. If you build a website but misconfigure MX records, the website will not be accessible normally. When solving the problem, you need to clarify the business needs first. The main domain name of the website is usually configured with A records or CNAME records, and the mail service needs to configure MX records. After confirmation, modify the corresponding record type.

2, parsing record value filled in the wrong

many users will mistakenly fill in the server Internet Protocol Address or domain name target value, such as filling in the IPv4 address as an IPv6 address, or the CNAME record points to a non-existent domain name. When encountering such problems, you need to check the correct IP or target domain name provided by the server, and then go to the background of the domain name service provider to modify the resolution record value. Save it and wait for it to take effect.

How to deal with domain name resolution security problems?

as the cyber security situation becomes more and more severe, domain name resolution may also encounter malicious attacks or unauthorized modifications, which will lead to problems such as domain name hijacking and website jumping to malicious pages.

1, domain name resolution records were maliciously tampered with

If you find that the domain name points to an unfamiliar server address, there is a high probability that the resolution record has been maliciously tampered with. At this time, you need to immediately modify the login password in the background of the domain name service provider, turn on the secondary verification function, and prevent the attacker from logging in again; at the same time, delete the abnormal resolution record and restore it to the correct configuration. If necessary, you can contact the domain name service provider to freeze the resolution authority. After the security risk is eliminated, it will be restored.

2, suffered DNS hijacking attack

DNS hijacking can cause users to be redirected to malicious websites when visiting a domain name. Such attacks usually target local DNS or intermediate links. When resolved, you can replace a safe and reliable public DNS server to avoid using DNS services of unknown origin; at the same time, configure the DNSSEC security extension for the domain name, which verifies the authenticity of the domain name resolution record and prevents tampering.

four, domain name resolution abnormal impact mail service how to do?

in addition to website access, domain name resolution also directly affects the normal operation of mail services, many enterprises will encounter the problem that mail cannot be sent or received, mostly related to MX, SPF and other analysis record configuration.

1, MX record configuration error

MX record is the core domain name resolution record responsible for mail routing. If the MX record is not configured or misconfigured, the mail will not be delivered normally. When solving the problem, you need to confirm the MX record address and priority provided by the mail service provider. For example, enterprise mailboxes usually provide multiple MX records. The smaller the priority value, the higher the parsing priority. It needs to be filled in and saved in strict accordance with the requirements of the service provider.

2, SPF records are missing or misconfigured

SPF record is used to verify the legitimacy of the email sending source. If it is missing or misconfigured, the email sent by the enterprise may be determined as email spam by the recipient. When configuring, you need to add the Internet Protocol Address or domain name of the mail server to the SPF record. The format is usually v = spf1 ip4: xxx.xxx.xxx.xxx~ all. After the configuration is completed, the validity of the SPF record can be verified through the online tool.

sum up, the common problems of domain name resolution are mainly concentrated in the four aspects of effective delay, configuration error, security attack and email service impact. The corresponding solutions are all around cache cleaning, configuration verification, security reinforcement and special project record adjustment. As long as you master these core investigation ideas, you can quickly locate and solve most domain name resolution related problems, and ensure the stable operation of the website and enterprise business.