Firewall / PPTP problems

[NeilC]

Any networking guys out there help me or point me to a good forum or something for this?

I have an ADSL connection with a UK ISP and am using a Huwei SmartAX MT882 modem. This mostly works OK.

However when I try to VPN into work using PPTP protocol I can connect and it works for a bit (pretty slowly) but then tends to disconnect and my modem hangs in some way and I lose my connection entirely. I have to reset the modem manually and then it works. This happens every time - it might take 10 seconds to happen, it might take an hour. It does actually connect and work fully when it works so data is making it past the firewall.

Any idea what is happening here? Why would PPTP jam my modem like this? Do I need to look at port forwarding?

 

[D2011]

a Huwei SmartAX MT882 modem. This mostly works OK.

Have you checked the manufacturers website for the latest firmware for this modem & reflashed it? When you say "mostly works ok". Do you mean just your general internet browsing when not using pptp suffers as well?

Have you tried to isolate the problem? E.g. Have you tried creating the pptp connection from another pc which uses different hardware & isp using the same login credentials you are failing with at home? If it works from another location , it is your pc or hardware. If it doesnt, the encryption policy or remote access policies may have changed.

Is your pptp connection between your pc & a work router? Or an RRAS/RADIUS server at work?

Do you have access to the administrators side of your works network?

There can be many variations in the scenario you describe, but the first step would be to try the above test I mentioned.

Do I need to look at port forwarding?

No. If you have established a pptp connection you have been assigned an ip on your works lan & have a virtual tunnel between yourself & them. If your work is using RRAS, then yes, at their end they would have to forward port 1723 to the RRAS server. But since you say your connection stays alive for up to an hour, this must have already been done.


D2011

 

[Ducky]

Is the IP of your modem static? If your IP is dynamic then every time your lease expires it could bounce your VPN.

 

[ShowMe]

Check with your ISP. Here in the States there are several that do not allow port 1723 or the GRE protocol; according to them telecommuters take up too much bandwidth.

It's not something that they advertise, of course. but I've run into it with several of my users.

 

[Arkan_Wolfshade]

Check with your ISP. Here in the States there are several that do not allow port 1723 or the GRE protocol; according to them telecommuters take up too much bandwidth.

It's not something that they advertise, of course. but I've run into it with several of my users.

That my first thought as well. They also try to force people who VPN to have to get "business accounts" for their home at times.