DR or domain rank is a metrics by Ahrefs which was introduced to index and rank sites by ahrefs. But now SEO specialists use it to mark site quality and filter sites for SEO works.
So, a site with DR 60 is good over DR 30 irrelevant of DA of the domain. So, if we have DA 10 and DR 60 versus DA 60 and DR 10, the first is the better one for SEO, as it has more quality links and chances are more of traffic.
So, SEOs will only do find guest posting and link building opportunities on sites with High DR.
Domain Ranking is a search engine ranking grade or score that ranges between 0-100. It gives grade Moz which is a popular company offering many SEO tools in USA.
Domain Ranking shows how likely your domain is to rank in the search engine. The higher the score of the blog, the more it will show further in the ranking.
That is, the score of one website is 30 and that of the other is 40 and a website with 40 rank will be in the top of the search engine results pages (SERPs).
For example, you can look at Wikipedia, whose domain score is 100 and its pages are always on the top of the search engine.
Domain ranking depends on many factors. If you are thinking that you have started a blog today and the domain rank of your blog will be 40 to 50 then it is not possible at all.
To increase the domain ranking of the website, you will have to work on SEO. It is very easy to increase Domain Ranking from 15 to 30 but if we talk about 65 to 75 or 75 to 85 then it is very difficult.