Re: checking if e-mail address and syntax are valid

On Tue, Apr 24, 2001 at 02:33:18PM -0700, Szii wrote: > Checking to see if it's "syntactically correct" is trivial. Validating the > domain is rather simple as well (check the retcode on a whois lookup.) Which is not as trivial as it sounds, since whois does not really have "return-codes". You need to know in advance how this particular whois-server is responding. (since most whois-server just serve a few TLD you might not even use only one whois-server). Even the output of a general whois-server like whois.thur.de (you can query pretty much everything on it) differs from TLD to TLD (since all whois.thur.de is, is asking the actual whois-server for that TLD.) It's probably much easier for validating a domain to use the mx-record-function. > Again, it's not "real-time" validation of anything except the > existance/validity of the domain - not the user. If your php-scripts looksup the mx-record for the domain and delivers directly to the mx for the domain, you might be able to verify in real-time, since you will get the return-codes of the mx. However not all mx'es deliver locally. As soon, as the mx passes the mail onto a different host for delivery (and there quiet a few of these around...) you can't verify. So basically, yes, you can lookup the domain, verify that the domain as a valid mx, but that's pretty much it. -fkr -- gpg-fingerprint: 076E 1E87 3E05 1C7F B1A0 8A48 0D31 9BD3 D9AC 74D0 |http://www.hazardous.org/ | whois -h whois.ripe.de FKR-RIPE | |all your base are belong to us | shame on me | fkr@IRCnet |