On Wed, 2010-09-15 at 12:14 -0700, Vitaliy wrote: > We started having problems with emails getting blocked by one of our=20 > vendor's mail servers: >=20 > : > 123.65.145.12 failed after I sent the message. > Remote host said: 551 Message contains ZIP file that is too deep (4) (Mod= e:=20 > normal) >=20 > The president of their IT company said this: >=20 > "Even though the manufacturer allows it, I would not put a zip archive=20 > inside other zip archives as a standard practice. The path to the archive= d=20 > file can be too long, thus the message that the "zip file is too deep". >=20 > Just to let you know, it is also a standard virus ploy (hiding infected=20 > files or malware inside a clean archive) that is no longer allowed by man= y=20 > RFC-compliant mail servers. " >=20 > I did a search out of curiosity, but could not find the RFC in question. = Is=20 > he full of it? I think you misunderstand his statement. He's saying that many mail servers, which happen to be RFC compliant, do not allow it. He's not saying it's disallowed my the mail server. As for the issue, yes, it's common practice by malware to multiply zip the payload, the assumption being that the anti-malware software will only "unzip" a certain number of times. I can't confirm that mail servers reject emails because of this. TTYL --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .