IP

Does DNSPod DNS support IPv6-only environments?

DNSPod supports IPv6-only network environments with verified performance within and outside the Chinese mainland.

An iOS app passes the local test but is rejected when submitted to the App Store. Why?

• Check whether the issue is caused by a DNS resolution failure
  How can you verify whether the DNS server responds correctly to the DNS request to an IPv6 address? After setting up the DNS64 environment, you can query it by running the following command:

$ dig dnspod.cn aaaa

The reason for verifying DNS resolution is that the first step for the app to access the internet is to perform DNS resolution. When App Store reviews the iOS app, it will first access the DNS server, get the IPv6 address of the app server, and then access it. If the DNS server cannot resolve successfully to the IPv6 address, even if the app passes the test in a locally built IPv6-only environment, it will still be rejected by App Store. Therefore, it is vital to choose a DNS service that has both high stability and compatibility.

• Poor cross-border cross-network connection quality
  DNS generally completes GEO region-specific resolution through an IP address library, but IPv6 does not have such an address library, so all IPv6 addresses are resolved to the address of the default split zone. If the default split zone is set to a China Telecom or BGP IP (for CAP, the default value is China Telecom), it will be much likely that the connection from an overseas location will fail due to the poor cross-border connection quality of China Telecom, leading to rejection by App Store. We recommend you:
• Modify the default IP of the domain for the features required during the review to a China Unicom or China Mobile IP.
• Connect the features required during the review to ECDN to speed up cross-border access.

How do I make an iOS app support IPv6-only environments?

Currently, there are three ways to enable an iOS app to support IPv6-only environments as detailed below:

• Connect all domains in the app to DNSPod
  Both DNSPod's underlying DNS resolution and domain resolution support IPv6-only environments, ensuring that businesses are successfully resolved in IPv6-only environments. The iOS app server doesn't need to support IPv6, as in IPv6-only environments, DNS64/NAT64 can translate IPv4 addresses into IPv6 addresses.
• Transform the client
  For example, you can transform the client to fix issues with direct IP access or upgrade the SDK APIs to make them compatible with IPv6.
• Set up and verify the environment
  Set up an IPv6-only hotspot as instructed in Supporting IPv6 DNS64/NAT64 Networks and connect to it through an iPhone for testing.

Can DNSPod DNS hide IP addresses?

No, as DNS maps domains to IP addresses.

After deleting or suspending a record, why can I still get the IP by running the ping command to connect to the domain?

This is caused by the cache of the local ISP's server (recursive server). Please wait patiently for the local cache to expire. Theoretically, the cache will expire after the TTL set for the record elapses.

Why are the resolution result of my domain and the resolved IP different?

We recommend you use the Domain Diagnostic Tool in DNSPod's Help Center for diagnosis. If you changed the DNS service provider less than 72 hours ago and changed the host address, please wait patiently for the change to take effect.

In intelligent DNS, why is a China Unicom user resolved to the IP of a China Telecom server?

1. First, check that the used network is not Hangzhou Wasu or Beijing Great Wall Broadband Network.
2. The record in DNSPod was configured less than 72 hours ago. Please wait patiently for it to take effect.
3. The China Unicom host is down, so D-Monitor automatically switches the record value of the China Unicom split zone to the IP of the China Telecom host. After the China Unicom host is back online, the record value will be automatically switched back to its IP.
4. Check whether the local DNS matches the split zone, and if not, modify the local DNS.
5. Check whether the domain is configured to point to a specified IP in the local hosts file.

After the IP is changed for a domain, why do search engine spiders still crawl the previous server?

Different search engines have different update periods (at least one week). After the IP is modified for the domain, search engines need a certain period of time to update. Please wait patiently.

Why is an IP blocked?

An IP will be blocked if more than 5 wildcard records are added for it over a short period of time and all of them point to it.
If an IP cannot be added as it is blocked, please submit a ticket to contact technical support.

What if my website is accessible to China Telecom users but inaccessible to China Unicom users?

First, ask China Unicom users to ping your domain in the cmd window to see whether an ip is returned:

1. If an ip is returned, the DNS resolution process works properly, and we recommend you submit a ticket for troubleshooting.
2. If no ip is returned, the command nslookup needs to be used for further testing, and you need to save the screenshot of the testing result and paste it into the ticket, so that we can perform further testing to identify the cause.

How long does it take for a record change to take effect?

A DNS record change theoretically will take effect after the TTL previously set for it elapses. However, a local ISP may forcibly extend the validity of the original record.

After deleting or suspending a record, why can I still ping the IP?

This is caused by the cache of the local ISP's server (recursive server). Please wait patiently for the local cache to expire. Theoretically, the cache will expire after the TTL set for the record elapses.

After the IP is changed for a domain, why do search engine spiders still crawl the previous server?

Different search engines have different update periods (at least one week).
After the IP is modified for the domain, search engines need a certain period of time to update. Please wait patiently.