Regex Tester & Validator

This regular expression matches specific ESET Antispam module domain names used in DNS queries, such as `h1-ars01-v.eset.com` or `h3-ars06.eset.com`. It validates hostnames starting with 'h', followed by a character class including digits 1, 3, and 5, and an 'ars0' identifier, concluding with the `.eset.com` top-level domain. It is useful for network administrators configuring DNS filtering, firewall rules, or analyzing traffic logs related to ESET security software. Note that the character classes in the regex technically include commas, likely due to a syntax error by the original author.