::why metropcs doesn't work with @pktpix
The short and sweet version
When you send an e-mail to anyone, your message has to have a couple of fields, but most importantly, your address (the sender), and the address you're sending to (the recipient). If your carrier says you can send e-mails, then it's safe to assume you have a valid e-mail address, right? Not for MetroPCS users.
The nitty gritty
When you send an e-mail out from a MetroPCS phone, the e-mail address they assign to your phone is "13135551212/TYPE=PLMN@mms.metropcs.net" (what your recipient sees). This is strange for three reasons:
1) The address that people use to send to a MetroPCS phone is "13135551212@mymetropcs.net", not "mms.metropcs.net". So technically, MetroPCS should be using the same address to send your e-mails out.
2) The extra crap, "/TYPE=PLMN", is likely some sort of internal identifier used by their MMS gateway, and doesn't need to be seen anywhere outside of the MetroPCS servers.
3) The biggie: that e-mail address does not work at all. Here's a quick briefer on Internet e-mail architecture:
Why does your e-mail work with other people, but not @pktpix? Because we have very strict anti-spam methods in place: one of them being sender address verification. 2) The extra crap, "/TYPE=PLMN", is likely some sort of internal identifier used by their MMS gateway, and doesn't need to be seen anywhere outside of the MetroPCS servers.
3) The biggie: that e-mail address does not work at all. Here's a quick briefer on Internet e-mail architecture:
When you send an e-mail address, your mail server does a lookup on the domain you're sending to, for what's called a "MX" record. The MX record defines what servers are eligible to receive mail for this domain.
If your domain doesn't have any valid MX records, you're not entirely SoL, because the next standard method is to try and connect to the domain directly. Now, what if the domain doesn't answer? Then you're screwed.
So herein lies the problem: when we attempt to connect to MetroPCS servers to verify that it's a valid e-mail address, we can't connect, and your message gets tossed.$ host -t mx mms.metropcs.net mms.metropcs.net has no MX record
If your domain doesn't have any valid MX records, you're not entirely SoL, because the next standard method is to try and connect to the domain directly. Now, what if the domain doesn't answer? Then you're screwed.
$ telnet mms.metropcs.net smtp Trying 65.91.116.37... telnet: connect to address 65.91.116.37: Connection refused telnet: Unable to connect to remote host
NOQUEUE: reject: RCPT from srvr-dns2.metropcs.net[65.91.116.51]: 450 4.1.7 <13135551212/TYPE=PLMN@mms.metropcs.net>: Sender address rejected: unverified address: connect to mms.metropcs.net[65.91.116.37]: Connection refused; from=<13135551212/TYPE=PLMN@mms.metropcs.net> to=<13135551213@pktpix.com> proto=ESMTP helo=<SRVR-DNS2.metropcs.net>
So those of you using MetroPCS, feel free to forward this on to customer service. You're more likely to grab their ear and attention than us random souls at @pktpix.