Anyone used openvpn

liven

Some might remember the little write I did about securing your wifi with ipsec tools, racoon and freebsd.

Well I have been using it for a while and really liking save one thing. One of my many laptops on the wifi has trouble negotiating security and connecting to the VPN from time to time.

So I decided to try another one of the open source vpn tools available.

Perhaps the most well known open source vpn is OpenVpn.

I got it up and running and overall I like it very much. By default it is TLS not IPsec, but none the less it serves its purpose. The performance form Ipsec tools seems to be slightly faster than OpenVpn, and Ipsec tools was much easier to get running. But OpenVpn community is MUCH bigger and OpenVpn seems to have many more options and configuration possibilities. Plus there is a GUI client you can install for the Windows machines which makes configuration on that end much easier. Once again if anyone is interested in instructions let me know and I will try to post them (eventually, working on several projects at once hahahaah).

Now to my issue. After getting this all working with OpenVpn, I am having an odd issue.

When I browse to some websites (ESPN.com for example) and click on certain links I get an error message:

This page contains no data

It takes about 30 to 60 seconds for this error to pop up. And if I turn the VPN off the error goes away. The links are links to third party articles, like news papers and things that like that. These links cause me to browse away from ESPN's site.

I have not seen the error on any other pages. I am certain that it has something to do with the VPN, but can not figure out what. My only other guess would be NAT, however all other things effected by NAT are working (example: FTP).

If anyone has any suggestions let me know.

Mishra

Did you try a different computer to see if it works?

Are you clicking on SSL sites? Try to find a familiarity between sites that work and don't work. Like maybe ESPN has ASP pages or something.

dtlokee

My guess would be some sort of MTU issue with the remote sites or possibly a firewall dropping IP fragments due to the added overhead of the VPN causing fragmentation.

liven

dtlokee wrote:

My guess would be some sort of MTU issue with the remote sites or possibly a firewall dropping IP fragments due to the added overhead of the VPN causing fragmentation.

This seems to be the consenus of the openvpn community.

However I tried to match up the MTU settings and still have the same issue.

TO be honest I have not messed with it as much as I should.

But thanks for your input, it is good to know that several experts seem to agree on the possible cause.

Now I just have to make sure that all the configurations are setup correctly.