LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices


Reply
  Search this Thread
Old 07-31-2007, 02:38 AM   #1
nehsmac
LQ Newbie
 
Registered: Jul 2007
Posts: 2

Rep: Reputation: 0
ppp stalls - tcp packet number reset?


My VPN connection to my work server is experiencing stalls / timeouts. This issue only seems to occur when I connect through linux. WinXP connections do not seem to experience this. In Linux, I am currently using gnome network manager, but the problem also occurred when I was using pptpconfig. This issue seems to be related to the expected TCP packet number suddenly jumping to a higher value. Here is an example of the output from /var/log/daemon.log:

Jul 31 00:49:13 nhamilton-ubuntu pptp[14136]: anon log[decaps_greptp_gre.c:407]: buffering packet 11685 (expecting 11679, lost or reordered)
Jul 31 00:49:13 nhamilton-ubuntu pptp[14136]: anon log[decaps_greptp_gre.c:407]: buffering packet 11686 (expecting 11679, lost or reordered)
Jul 31 00:49:13 nhamilton-ubuntu pptp[14136]: anon log[decaps_greptp_gre.c:398]: discarding duplicate or old packet 11687 (expecting 11744)
Jul 31 00:49:13 nhamilton-ubuntu pptp[14136]: anon log[decaps_greptp_gre.c:398]: discarding duplicate or old packet 11688 (expecting 11744)

When I monitor the log during network operations, I do notice a lot of the "buffering packet #, expecting packet #" messages, but I assume that is just normal TCP protocol for dropped/lost packets. At some point the expected packet number jumps to a larger number (11744 in this example) and the buffering messages turn into the "discarding duplicate or old packet" messages. The discard messages continue to spam the log until I kill the connection, and all network traffic times out during this period. This does seem to occur most frequently when I attempt to perform high throughput operations, such as SCP'ing a large set of files or performing a subversion checkout on large binary files.

So far I have not been able to find much on this issue. The only troubleshooting I have come across is changing options in the /etc/ppp/options file, such as changing the values for lcp-echo-interval and lcp-echo-failure, which has not helped.

Here are the relevant configuration options I am using for gnome network manager:
- Type: PPTP (Windows VPN)
- Refuse EAP
- Require 128-bit MPPE encryption
- Use Peer DNS
- Exclusive device access (UUCP-style lock)
- Peer DNS through tunnel

Has anyone experienced similar issues with vpn connections?
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
scp stalls using ppp/pptp vpn fpiergen Linux - Networking 0 12-11-2006 09:49 AM
TCP Packet Size ajkannan83 General 3 11-03-2005 06:46 AM
PPP stalls under moderate CPU load Alucard243 Linux - Networking 2 07-09-2005 02:46 PM
tcp packet size dellcom1800 Linux - Networking 2 07-28-2004 07:49 AM
RH9 ppp stalls tumbledown Linux - Networking 2 08-04-2003 01:10 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 06:58 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration