Firstly sorry for the 10,000th Reg Ex question, I realise there are other domain related questions but the regex is either not working properly, too complex, or for urls with subdomains, protocols, and filepaths.Mine is more simple, I need to validate a domain name: So a domain in its rawest form - not even a subdomain like 4 revised: TLD should actually be labelled "subdomain" as it should include things like uk -- I would imagine the only validation possible (apart from checking against a list) would be 'after the first dot there should be one or more characters under rules #1 Thanks very much, believe me I did try! When it comes to uk, and some Japanese domains, I'm sure you will have to think twice before using regex for that.
All the dns lookups or regular expressions aren’t going to save the customer from himself if he’s just stubborn from the start and puts in a “valid” but fake e-mail.
That’s a good question Michel, I’d have to look into how to define allowable Unicode characters with PCRE. I prefer to stick with functions that are native to PHP 4 for the sake of backwards compatibility.
The regex you have written is only validating after one dot..write the regex modifying it by putting similar regex by putting one more dot and similar regex....i know this answer is vague..post the regex meanwhile...
Is there a quick and dirty way to validate if the correct FQDN has been entered? Note that a registerable TLD can have more than one component, such as "co.uk". The rules are designed to prevent such things as mixing characters from left-to-right and right-to-left sets. regex is always going to be at best an approximation for things like this, and rules change over time.
I’ve had to retort to a very simple regex which just checks for an @ sign, something before it, at least one dot after it and at least 2 letters in the last suffix.
Following that, I actually do a DNS lookup behind the scenes to check that the domain is registered, and following that, I use a funky little networking hack to check for an MX record in the domain’s DNS records - if it has an MX record, I allow it to pass.Developer Resources Java JAR Files DLL Files DBA Resources Software QA Resources On-line Testing Tools Programming Tutorials Biotech Resources File Extensions Security Certificates Link Directories Windows Tutorials Interview Q & A FYIcenter Forum As a software developer or tester of Web applications, you may be required to know what is a valid domain name and what is an invalid domain name.A valid domain name must satisfy a number of requirements.This page allows you to learn and test domain name format again those requirements. A domain name is an identification of a unique computer system on the Internet.A complete domain name consists of one or more subdomain names and one top-level domain name separated by dots (.). A complete domain name is valid if it meets the following criteria: How to test domain name format?I think a few people are missing that this Reg Exp validates the format of a domain name, not an email address.