When trying to browse any website, such as nytimes.com, yahoo.com, etc, it take sometimes anywhere from 15s-120s for the page to display. For example, in Chrome, when I browse to nytimes.com, in the status bar, I see the message "waiting for css.nytimes.com" or "waiting for www.nytimes.com" for a long period of time.

This is happening at home (on VPN to my employer's network or off) as well as when I'm connected to my employer's network directly. The problem occurs on all browsers on my Mac [Chrome, Safari, Firefox] and the curl command line tool in Terminal.

This problem seems to be isolated to my Mac. For example, when I browse on my iPhone (or my Windows laptop or another Mac laptop) on my home network, performance is great. It's terrible on my Mac. So this is definitely an issue with my Mac (OS Mountain Lion). This seems to be isolated to HTTP/HTTPS and not all TCP traffic since I can use SSH/RDP w/o any issues.

Using Activity Monitor, I can see ample free RAM and CPU utilization is minimal. I noticed this problem a couple of weeks ago. A reboot clears it up and then after 2-3 days, browsing starts to slow down again. Some pages take minutes to appear (or some suddenly appear in a flash when I stop loading the page).

What can I do diagnose the cause?

  • Please add within your OQ if your local connection is an Ethernet, a Wi-Fi or a Bluetooth one? Specify if this uplink can change without your control: are you using the famous Automatic network configuration?
    – dan
    Feb 27, 2015 at 13:14

4 Answers 4


I have the Cisco AnyConnect agent installed, which is only used for VPN and not Web Filtering. Still, the acwebsecagent process is running and slowing down my web browsing.

To uninstall acwebsecagent, run: sudo /opt/cisco/anyconnect/bin/websecurity_uninstall.sh

Credit to this post for the above command.


You didn't specify the brand of VPN software, but the process you cited leads us to the Cisco AnyConnect client. A quick search turned up a blog post tracing similar problems no the default install options for the Cisco AnyConnect client. THe punch line is that an uninstall then custom reinstall of that software seems to have cleared the problem up for several users.

Here is the post.

Hope this helps.

  • I was going crazy with the same issue. I had narrowed it down to Cisco's anyconnect, but this is the root of the problem. Thank you. Mar 17, 2014 at 0:15

Since the problem doesn't seem to be the network

  • What are your proxy settings (Settings.app -> Network -> (select current uplink) -> Advanced -> Proxies -> Any setting with a checkmark)?

  • What are your DNS settings? (Same as above, different tab)

    • If it's a local address what sort of router do you have? (and if it is, this'll probably be something to address again if other options don't give any good indicators)
  • Is there any flak in Console.app (/Applications/Utilities) that could relate to networking?

If the problem seems to be the network after all

Since you seem to be at home in the terminal, try either of the following

  • Use traceroute -q 10 (easy, as it is built in; sends 10 pings to each hop)
  • Use mtr - mtr is available in MacPorts (preferred as it gives better data, but a hassle if you don't have at least MacPorts)

Either way, here's how to read the results (it's an mtr help document, but the information is sane for traceroute). If you're in doubt, post that result and I'll gladly help read it.


  • 1
    No proxies are set. The only DNS entry is, which is my Asus router. I suspect the culprit might be acwebsecagent process, which is part of VPN software I have to use. I'll do more investigating and report back. The problem is now that the slowdown is gone.
    – Sajee
    Nov 10, 2013 at 2:18
  • Presumably because your trafic isn't going the same way (inside or outside of the VPN, through Wi-Fi or through Ethernet or through Magic).
    – dan
    Mar 1, 2015 at 16:38

I have a very similar scenario to yours. I found this on Stack Overflow and it did the trick. Worth a try.

Delete all files in /Library/Preferences/SystemConfiguration and force OS X to recreate new preference files.

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