Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
I am tunnelling private data through an untrusted network (which I do not control) to a Zyzel router Prestige 334 to be exact. The Zyxel has our clients plugged into it.
The tunnel is dropping in and out frequently. When I turned on logging at the linux server end; I found that GRE packets were missing.
The log would say something like:
GRE : accepting packet #3440
GRE : accepting packet #3441
GRE : buffering packet #3443 (expecting #3442, lost or reordered)
GRE : buffering packet #3444 (expecting #3442, lost or reordered)
GRE : buffering packet #3445 (expecting #3442, lost or reordered)
GRE : buffering packet #3446 (expecting #3442, lost or reordered)
I can see packet 3442 did not arrive. It is lost in the etha somewhere. The LAN I am tunnelling though has a switch on each flor of the building and a fiber connecting the switches.
The people who run this network deny that packet loss occurs on their network, and probably have no idea.
I have changed the MTU and MRU inside the pptp server to 1300 with no improvement.
Does PPTP and GRE have any knid of retry mechanism?
Typically are packets only sent once and expected to arrive?
Is there any way to set up PPTP to tolerate Packet LOSS?
I would like to add, that In this case the untrusted network is not open internet, and I am not running any encryption. So stateful encryption issues wont bother me here.
I was thinking, of changing some PPP option to tolerate and accept packets out of order, rather than buffering and waiting for the right one. I can not find such an option.
According to the RFC, some GRE loss could be tolerated by a decryptor provided that a higher layer stateful encryption is not used.
To be 100% clear, The packet loss is the GRE raw packets themself, not data inside the GRE tunnel.
The entire link fails and reconnects, resetting sequence to zero, and re negotiating.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.