Re: Validating email addresses

["David Gibbs" <dgibbs@xxxxxxx>]

<rob@dekko.com> wrote in message
OF380692F4.1ED1B864-ON05256BA6.0068460A@dekko-1">news:OF380692F4.1ED1B864-ON05256BA6.0068460A@dekko-1...
> The solutions:
> - ruled out "finger" because often blocked

And rarely active if it isn't blocked.

> My question is the following acceptable
> PING RMTSYS(&domainpart) MSGMODE(*QUIET *ESCAPE)
> MONMSG TCP3210
> versus the hassle of coding gethostbyname, or is ping often blocked?

Ping is blocked sometimes ... especially with DSL connections, as ping eats
up bandwidth and can be used as a DOS attack.

> Correct me if I am wrong but if I entered a nonexistent host table entry
> like ralph.huey then gethostbyname would find it since there is a host
> table, or a DNS entry, for ralph.huey.  Granted, you'd have to have a
> really hosed up host table for this to be of a real concern.  But ping
> would report the error.

Yes, ping would report the error.

What system are you going to ping to validate the email address?  Keep in
mind that many (if not most) companies do not point their main domain name
to the same system that handles their email.

Way (way way) back when I first setup midrange.com, if you pinged
midrange.com you would get nothing... but if you sent me email, it would
arrive, because the mail exchanger (MX) record in my ISP's DNS pointed to a
valid system.

The *BEST* way to validate email addresses is to send out a message and ask
for a reply.  Unfortunately, it does require a human response.  You can't
even count on a mail system sending a "bad user" response if you have it
setup wrong.  Additionally, the various mail servers have widely differing
response mechanisms... it's very difficult to program for all of them.

david