Iran's authorities this week launched a new, sophisticated offensive against the Internet, stifling Gmail and other messaging services and totally blocking software that provides secure browsing.
The severe clampdown has prompted an outcry by media, businesses, students and private web users, and has even provoked criticism within the regime.
"E-mails have again been cut and the patience of (Internet) users is at an end," the ISNA news agency reported, highlighting the 'disruption' for those needing online tools for their profession.
"Authorities were playing with the nerves of Internet users," the reformist newspaper Shargh said in a front-page article.
The website Alef.ir, belonging to an influential MP, Ahmad Tavakoli, complained about the 'numerous problems' created by the offensive.
"No communications official or security service has given any explanation about this measure. Apparently those who ordered it attach no importance to public opinion or the discontent created by their action," it wrote.
Iran has strangled the Internet from time to time in the past, extending a permanent censorship of millions of websites it deems un-Islamic.
The last time was a week ago, when Gmail, Hotmail and Yahoo e-mail services were cut or slowed to an unusable speed.
This time, however, the attack has gone further, completely stopping the use of Virtual Private Networks (VPNs) -- software that enables secure Internet connections.
VPNs, which are often used worldwide by corporations, were commonly used by many of Iran's 33 million individual Internet users to get around the web censorship.
The head of the Iranian parliament's new technologies department, Reza Bagheri Asl, said the block was creating hardship for "banks and financial institutions (which) use this protocol for its heightened security to exchange information."
The new and systematic block on VPN use appeared to be part of plans by Iran to roll out its own 'national Internet' -- a totally closed system that would function like a sort of intranet for the Islamic republic.