A company that runs a VPN service for Iranian customers said that attempts by the government to block the service over the weekend have failed.
But the owner of a Brazilian VPN says that it has been unaffected.
Joshua Van Raalte said that the users of the "Hide My Ass" free proxy have not been affected.
He thinks that this latest attempt at internet restriction is likely to be largely futile.
Van Raalte said that the block on VPNs was confirmed by a local protester on Facebook which is supposed to be a banned site in Iran.
"The Chinese government has also spent years and millions of dollars on technology intended to block VPNs, and yet they still get through regardless," Van Raalte said.
He added that the provision of proxy technology, tools and software has so far managed to evade all attempts at censorship.
More than 1,200 Iranians use HMA's free proxy service every week, even though it is officially "blocked" by the Iranian government.
Van Raalte said that HMA will continue to support users from Iran as much as it can in order to promote openness, and the global freedom of expression provided by the internet.