Question : server dropped connection without sending the initial greeting

I am running postfix server. One of my users is trying to send an email to verizonwirless.com and postfix is droping the connection. I cant figure this one out, why am I getting this error:
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Apr  3 05:05:13 mail1 postfix/smtp[12542]: 81A218CA83: to=<******.******@VerizonWireless.com>, relay=none, delay=306603, status=deferred (connect to mercury.verizonwireless.com[162.115.227.109]: server dropped connection without sending the initial greeting)
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I confirmed that mail was going to the right location
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nslookup -q=MX VerizonWireless.com
mercury.VerizonWireless.com     internet address = 162.115.227.109
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The funny thing is that it takes a good 5-8 seconds for the initial greeting from verizonwireless.com email server when I
"telnet mercury.VerizonWireless.com 25"

I do have "smtpd_helo_required = yes" in my main.cf
Could smtp_helo_timeout be the trick?

Answer : server dropped connection without sending the initial greeting

Yes, that sounds reasonable. You may also want to try smtp_connect_timeout parameter as well.

If you wanted to you could also setup a special transport table just for these types of difficult sites (such as Hotmail as well), assigning them to a special delivery agent that applies special timeout settings just for them.