In the latest analysis of Iran’s filtering of the Internet, it appears that they are getting very good at filtering at the ISP level. Arbor Networks looked at recent data and found some interesting results.
Looking at the graphs, ShaTel and Saba Networks show similar traffic patterns:
1.an abrupt drop off after the June 12 election
2.followed by a return to near normal levels around June 16
3.and then a significant June 27 to June 19 80% drop in traffic
4.a rise in traffic on June 19
5.and then a drop in traffic again on July 21Interestingly, Pars Online was one of the few providers to gain traffic immediately following the June 12 election (suggesting diversion of traffic from other ISPs through Pars Online filtering infrastructure).
It also appears that capacity might be playing a part in dropped traffic, as well as filtering.
“It was speculated early on that they lacked capacity,” Labovitz says. “It wasn’t that traffic was being filtered, it was that it was being dropped because they lacked capacity. Now, it looks like they are navigating 5 gig of traffic again, and I don’t think they have turned off filtering.”
Since it is difficult to get accurate results out of Iran, it is difficult to predict what is causing the drops in traffic. However, the likely conclusion is that Iran is perfecting their Internet filtering capabilities and will, most likely, continue unabated in the future.

