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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-130 => Topic started by: Harrkev on February 08, 2010, 10:20:31 AM

Title: Web browsing through PPTP VPN seems broken.
Post by: Harrkev on February 08, 2010, 10:20:31 AM
I just got a DIR-130, and have had fun setting it up.  However, I am having a VPN problem.

I set up a PPTP VPN as described in the FAQ.  I set up Windows XP Home to use this VPN connection, and it connects just fine!  I can access my networked printer from across town very easily.  I can access my printer's web page just fine.  I can also access the router's own configuration web page just fine too.

However, when I try to access the general internet through the VPN connection, I have serious problems,  It appears that I can access www.msn.com just fine, and I can get to MANY links from www.msn.com.  However, if I try to go to any other pages craigslist, woot, google, bing, etc., then it appears to hang.  I have confirmed this exact same behavior using the Chrome browser.  Firefox, however, refuses to start until I disconnect from the VPN.  ???

Any advice?

** BEGIN EDIT **
Actually, I cannot access my router configuration page remotely.  I can, however, access my printer's configuration page, and my wireless access point configuration page.  I also tried completely disabling my firewall on Win XP Home, and still the same results.

I found that Thunderbird can SEND mail (SMTP), but cannot receive mail (POP).

I need this to work, because I want to be able to keep my passwords secret from snooping while using public unencrypted access points (book stores, coffee shops, etc.).
** END EDIT **


PS: Another problem that I found:  When viewing the DHCP clients table, setting a single DHCP reservation seems to wipe out the entire table.  Not a deal-killer, but kind of annoying.
Title: Re: Web browsing through PPTP VPN seems broken.
Post by: Fatman on February 08, 2010, 11:26:11 AM
Check the interface MTU on the PPTP interface.
Title: Re: Web browsing through PPTP VPN seems broken.
Post by: Harrkev on February 08, 2010, 12:04:46 PM
Thanks.  That did the trick!  You are da man!

Unfortunately, XP does not seem to provide a GUI to change this setting, so I had to do this:

http://support.microsoft.com/kb/283165

And, despite the instructions, setting the MTU to 1350 was needed to do the trick (1400 will not work).

A link to these instructions (or perhaps just a downloadable registry file) should be placed in the FAQ.

So, why exactly do I need to do this?  Shouldn't a packet that is too long be fragmented?

Thanks again!  You rock!

** EDIT **
Hmmm.  I just tried to search for MTU in the DIR-130 and DIR-330 forums, and very little came up.  Am I the first person to run into this problem?  I cannot believe that others have not seen this also.
** END EDIT **
Title: Re: Web browsing through PPTP VPN seems broken.
Post by: Fatman on February 08, 2010, 02:32:25 PM
Your the first one I have worked with pertaining to this product, or even the first one concerning PPTP VPNs I can think of immediately.

(Un)Fortunately your symptoms were classic symptoms seen fairly commonly on consumer class equipment using WAN connections with an MTU lower than 1500.

I would also check your WAN Type on you DIR-130 against your DIR-130's WAN MTU.

Fragmentation is very expensive computationally and under any kind of load can lead to connections being dropped, and a number of applications may set the DF (D'ont Fragment) bit which would just cause the frame to be dropped outright.

I don't htink this is a fairly common issue, not only because I had not seen it previously, but I fear your environment may have happened to be a perfect storm.

This is not expected to be accurate but I am picturing the following.
A cable connection with a WAN MTU of 1500 for your hotspot network
A DSL connection (MTU 1492) with your DIR-130

Meaning that you could fragment the incoming PPTP connection and then again when that tunnelled traffic leaves the DIR-130.  This would lead to the DIR-130 being a huge bottleneck whenever any remote clients are PPTP'ed in.
Title: Re: Web browsing through PPTP VPN seems broken.
Post by: ZubairKhokhar on November 24, 2013, 12:55:08 AM
I've got a DIR-615 with 5.10...
And I got a new internet connection with PPTP protocol.
I had this problem that it wasn't connecting but then I changed the PPTP server address to an ip instead of red.connect.net.pk. It connected. Now the problem I'm facing is that it connects but there is no internet access :S Please help me out!!!
I've tried almost everything. I'd be glad if the problem is resolved or I would have to buy a new router ???
Title: Re: Web browsing through PPTP VPN seems broken.
Post by: FurryNutz on December 05, 2013, 02:12:19 PM
Any status on this?  ???

I've got a DIR-615 with 5.10...
And I got a new internet connection with PPTP protocol.
I had this problem that it wasn't connecting but then I changed the PPTP server address to an ip instead of red.connect.net.pk. It connected. Now the problem I'm facing is that it connects but there is no internet access :S Please help me out!!!
I've tried almost everything. I'd be glad if the problem is resolved or I would have to buy a new router ???