Re: Validating email addresses

[rob@xxxxxxxxx]

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pinging ibm.com fails.  They must have blocked ping.  But this will work:

      /eject
 P*---------------------------------------------------------------------
     P* Procedure name: VALIDEMAILADDR
     P* Purpose:        Validates email address
     P* Returns:        '1'=Yes the email address is valid, '0'=No it is
not
     P* Parameter:      emailaddr => email address
 P*---------------------------------------------------------------------
     P VALIDEMAILADDR  B                   EXPORT
     D VALIDEMAILADDR  PI              N
     D EmailAddr                           LIKE(login.logemail) CONST

     D* Local fields
     D rValidEmailAdr  S               N
     D DomainName      s            100a
     D Start           s             10i 0

      /free
       Start = 1 + %check('@':EmailAddr);
       Select;
       When Start=1;  // no @ found
        rValidEmailAdr=*off;
       When Start>=%len(EmailAddr);  // in last position, going further
may bomb program
        rValidEmailAdr=*off;
       Other;
        DomainName=%trim(%subst(EmailAddr:start:%len(EmailAddr)-start+1));
        cmd='PING RMTSYS(' + %trim(DomainName) +
                  ') MSGMODE(*QUIET *ESCAPE)');
        ErrorFlag=system(%trim(cmd));
        Select;
        When ErrorFlag=*zeros;
         rValidEmailAdr=*on;
        Other;
         Select;
         When ErrorCPF='TCP3202';  // unknown location, bad
          rValidEmailAdr=*off;
         When ErrorCPF='TCP3210';  // 0 of 5 attempts worked, ping might
be
                                   // blocked.  We'll accept this.
          rValidEmailAdr=*on;
         Other;  // discard all other errors
          rValidEmailAdr=*off;
         EndSl;
        EndSl;
       EndSl;
       return rValidEmailAdr;
      /end-free
     P VALIDEMAILADDR  E

Rob Berendt
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin




rob@dekko.com
Sent by: midrange-l-admin@midrange.com
04/25/2002 02:11 PM
Please respond to midrange-l


        To:     midrange-l@midrange.com
        cc:
        Fax to:
        Subject:        Validating email addresses


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I was researching the thread "Validating email addresses" from
http://archive.midrange.com/midrange-l/200006/msg01538.html

The solutions:
- ruled out "finger" because often blocked
- suggested gethostbyname or gethostbyaddr
- suggested using a reply to address to process bounced back emails
- checking internet tables of blocked email addresses

There didn't seem to be anything, other than the bounce back, to truly
validate an email address.

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?
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.

Rob Berendt
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin
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