Are we sure about that? I don’t know much about the SMS and MMS protocols. And I remember when I had a phone that could only receive SMS, I’d get a link so I could view the message in the browser on a computer, so in that sense it is close to what you are describing. But from my limited understanding of SMS and MMS, I thought MMS is a distinct protocol.

Looking at something that Twilio writes about SMS vs MMS, they say [1]:

> MMS […] was built using the same technology as SMS to allow SMS users to send multimedia content.

and then

> Standard SMS messages are limited to 160 characters per message. If a message exceeds this limit, it is broken up into multiple segments of 160 characters each, depending on its length. Most carriers today automatically chain these messages together to ensure they arrive in the order they are sent. Unlike SMS, MMS messages do not have a standard limit. While their maximum size depends on the carrier and the device receiving the message, 300 KB is often mentioned as the largest size most carriers will reliably handle.

So MMS sounds like an extension of SMS, but a thing of its own.

I remember with another old phone I had, I’d be asked if I wanted to download the MMS messages I received. But not sure proxy server would be the word for it. To me, from my memory, proxy server seems to apply only when the device is not capable/not configured for receiving MMS.

[1]: https://www.twilio.com/learn/messaging/what-are-sms-and-mms