What should I do if php cannot resolve the domain name?

Solution to the problem that php cannot resolve the domain name: 1. Use the terminal command line to run the "# php -r "echo(gethostbyname('...'));";" command; 2. Change "libnss_dns .so.2 libnss_files.so.2 libresolv.so.2" is copied to the lib of the virtual host directory; 3. Restart php through "# amh php restart xxx.com".

The operating environment of this tutorial: linux5.9.8 system, PHP version 8.1, Dell G3 computer.

What should I do if php cannot resolve the domain name?

About the problem of unsuccessful domain name resolution in PHP

Please pay attention to using the virtual host panel to manage the system, especially the amh panel! !

I have been tormented to death these days. After installing the amh panel, all functions that use domain name resolution fail, such as gethostbyname, curl, sending emails and other functions. As long as the URL is a domain name, all functions fail. Just change it to the IP address. At first, I thought it was a DNS problem. After checking, I found that the ones used are 8.8.8.8 and 8.8.4.4. Moreover, pinging those domain names can also return the IP address correctly. NSlookup is also normal. The most weird thing is Yes, use the terminal command line to run:

# php -r "echo(gethostbyname('www.baidu.com'));";

It can actually return the IP, so I aimed at amh. It should be its problem. I searched online for a long time and asked many people, but I couldn't find it. The solution, later I accidentally learned about the chroot thing. After searching on Baidu, I found that this thing is to switch the system environment to a specified directory. The system environment outside the directory cannot be used. It includes dns resolution. It gradually became clear. So I checked which libs are needed to parse dns, mainly these three:

libnss_dns.so.2  libnss_files.so.2  libresolv.so.2

Now, here comes the point, the amh panel, if you encounter the same problem, check it out, cd to your virtual host directory ：/home/wwwroot/xxx.com/, there are etc, lib, usr, web, tmp and other directories below. Copy the three libs mentioned above to the lib directory of your virtual host directory

# cp /lib/i386-linux-gnu/libnss_* /home/wwwroot/xxx.com/lib/

Try it again now. Is it successful?

Oh, if I talk too much, I will shed tears...

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PS: After the last step is completed, remember to restart php, amh, direct command:

# amh php restart xxx.com

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