I am running openSUSE Linux, the Tumbleweed version. I discovered that it does not use an /etc/services file, though I do not know what is replacing it, or how it is done, and I do not have much success searching the web.
Actually, what happened to me is that my mail system stopped working correctly after a major system update, both in-mail and out-mail. After much testing and debugging with a more expert user (of other Linux distros), we discovered that the /etc/services file was missing.
Thinking it had been accidentally destroyed, we created a small one to provide at least for the ports used for email. And it did solve my mail problems.
To do things cleanly, I asked another openSUSE Tumbleweed user for his copy of the file as provided in the distribution. But he did not find it in his own system, which has no mail problem. So, it is not necessary.
Apparently, I had solved my problem by accident.
Could someone at least confirm that /etc/services is no longer normally used in this openSUSE Linux. But I would like an explanation of how things are now done, and if possible of why my problem was solved by adding /etc/services, and whether I could solve it without /etc/services.
(reported to the best of my understanding and memory of events)