Cisco’s VPN Client is crap…

I suddenly had a problem on my Mac that I couldn’t start the VPN client anymore — “Error 51” was the only thing I received.

Google pointed me to this site where I found some very helpful advice.


6 thoughts on “Cisco’s VPN Client is crap…”

  1. Well, I tried everything without success.
    1. I uninstalled CiscoVPN and reinstalled it. No luck.
    2. I manually deleted all files having to do with CiscoVPN and reinstalled it. No luck.
    3. The solution that worked for you still results in Error 51.

    At this point, I have run out of ideas. If you have any, please let me know.

    Happy 2010,


  2. @Pierre Divenyi: First, Happy New Year to you as well!

    Unfortunately I don’t have any advice for you besides restarting the VPN subsystem. That always did the trick for me — fortunately the problem disappeared some day (maybe after some Mac OS X 10.5.x update?).

    I’m now running Snow Leopard and haven’t seen the problem so far on this platform. *keeps fingers crossed*

    I hope that you will find a solution soon. Rebooting is the last thing you would like to do in such cases…

  3. the problem is with mac osx .
    when building a new profile the cisco vpn is working fine but the minute you reboot your machine the OSX does something to it.
    delete some files. to recover the vpn you could build a new profile and logon to it and you’ll see that the vpn is working just great.
    by the way the Microsoft Entourage also didn’t work until i build the profile from scratch. but still after reboot it happen again.

    in short mac osx sucks .
    it’s my first try on it and i hate already.

  4. @yuval attar: I would definitely not agree with your conclusion “Mac OS X sucks.”

    Mac OS X, as every other non-trivial piece of software, has bugs. Period. That’s basically a law of nature. You may like Mac OS X or not, but that’s a totally different thing.

    I’m not a Mac OS X addict or “nerd.” In fact I’m using Windows since almost 20 years, and Mac OS X only since 1.5 years, and I still think I can do lots of things faster under Windoze, compared to Mac OS X. Anyway, I must say that I really like Mac OS X. It’s not perfect (but there isn’t any OS that’s “perfect”), but compared to Windoze it also has a lot of advantages for me (especially for work), being Unix-based.

    Coming back to the Cisco problem: I was definitely a problem with Mac OS X, as it turned out later, because with some Leopard update it disappeared, I’ve never seen it since.

    OTOH, now with Snow Leopard, I don’t even have to install Cisco’s client, because the IPSec client built into Snow Leopard has full support for Cisco’s XAuth extension for IPSec. So I can even use it to log onto our corporate networks, using RSA SecurID tokens. I’ve only started using Snow Leopard’s client last week, so I’ve only used it a couple of times, but in general it seems to work well.

    If you still have problems with the Cisco client and are already using Snow Leopard by chance, give the built-in IPSec client a try! It may solve your problems…

  5. I’m having the same error 51 problem. I am using mac os 10.5.8 hardwired to the internet and get the error every time.

    I also use a laptop mac os 10.4 on a wifi connection to the same home network. Going wireless it works fine. But if I turnoff the airport connection and use a wired connection I get the error 51 message.

    Any ideas. I need to move large files and the wireless connection is a slow one.

  6. @alex: I haven’t seen this problem since a veeeery long time — even before I switched to 10.6 (Snow Leopard) — so unfortunately I cannot offer any advice to your problem other than to check whether you’re using the most current version of the VPN client, and if necessary upgrade to the latest and greatest build.

    BTW, Snow Leopard has a VPN client built into it. It mostly works fine, even supports the XAuth extension we need to support our RSA SecurID tokens, but sometimes even the built-in client has some problems (it can connect, but afterwards you can’t communicate with hosts inside the LAN I just dialled into). So there doesn’t seem to be a “perfect” solution that has no problems at all…

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