Limits of email (SMTP)

When I try to send an email with a large amount of atatchments varying in size of the Mega Byte rage. I will recieve a error 552 from my mail server. I looked this error message up and found a refernce to it in both RFC 821 and 788 section 4.5.3 Sizes

Acording to RFC 821 there are size limits on user, domain, path...

And if these limits are exceeded you may recieve one of the folowing:

500 Line too long.
501 Path too long
552 Too many recipients.
552 Too much mail data.

My question is:

Is these limits spasific to the individual mail server you are useing or are they universal limits?

Well I use both hotmail and yahoo and the limitations vary depending on what type of account you have.The free one I have is 6mb.

quota is dependant on the server. i.e. yahoo free accounts have a 6mb quota for your inbox.
That error via SMTP means the recipient's quota has been exceeded.

typically you have a hard coded quota and then a grace quota size, typically 1mb

Also quotas can be assigned to groups. i.e. users have 6mb quota, power users can have unlimited quotas, depends on the admin

"Is these limits spasific to the individual mail server you are useing or are they universal limits?"

RFC's are standards not laws. Most programmers will want their software to conform to these standards. Most smtp servers will adhere to the RFC's but you could change limits in the source code before you compiled it. I guess thats what spammers do :)