They used to be the only registrar for com., or at least Network Solutions was, before they got bought. Verisign owns one of the root servers, and I believe t

They used to be the only registrar for com., or at least Network Solutions was, before they got bought. Verisign owns one of the root servers, and I believe they are in charge of adding SOAs for all the com. domains. Though I suppose the other root servers could go rogue at any time if they wanted to. I think that all other registrars have to go through Verisign in order to register sub domains off of com., but there may be other ways. I haven't really kept up with it in the last 20 years.