Photo by Christian Wiediger on Unsplash

SLT is throttling your Internet

I experienced Sri Lanka Telecom (SLT) throttling my internet first hand! According to Twitter, I am not alone. If your are a SLT customer or if you believe in the right to Internet access in general, here is what you need to know and why we can’t let SLT get away with it.

The Hypothesis

  • SLT is throttling download speeds during “Off-Peak” (OP) hours
  • SLT is not throttling download speeds during “Peak” (PE) hours

The Experiment

Start downloading Ubuntu 20.04 LTS iso, 15mins before OP to PE transition. Download will be done using :

  1. Direct download — Using Free Download Manager (FDM)
  2. Torrent download — Using μTorrent

We will compare download speeds during OP and PE. Test will be done on a Fibre (FTTx) connection with “100 mbps max download” and “upto 50 mbps upload” advertised speeds.


  • Direct downloads showed no difference; downloads saturated the download bandwidth of 100 mbps
  • Torrent downloads were clearly throttled at around 6 mbps.The throttling would abruptly stop at 08:00. Please see video below which was captured from my computer:


  • SLT does not disclose Torrent throttling speeds in their package page:
  • But Ruvi, aren’t Torrents illegal?”.. NO!
    It’s the content that you download that makes it illegal and morally wrong. For example, in this demo, I am downloading an Ubuntu Iso file which is a perfectly legal usage of Torrents. Saying that Torrents itself is illegal is wrong, because it’s the content and not the technology that can be illegal under copyright law.
  • PS: I am by no way advocating for Piracy using Torrents. I am in fact a big anti-piracy advocate for ethical reasons. My claim to fame on this topic is how I went out of my way, jumping through many hoops, to pay for an Adobe Creative Cloud license when Adobe refused to take my money. Maybe a story for another time.


  • The legality of Torrents is besides the point. I used it for a 100% legal usage.
  • If SLT wants to throttle, that’s fine.. it’s their product.
    We as customers have the choice to vote with our wallet.
  • But they can’t be allowed to get away with covert throttling like this. It is a breach of contract and a violation of our freedom to access Internet.
  • ISPs like SLT need to be held accountable for such practices or I fear that left unchecked, this can only lead to more blatant violations.
  • I will be lodging a ticket with SLT to follow up on this. Watch this space for updates.

Embedded Systems & Linux Techie