#514274 Bad ppp frames for certain TCP package lengths

Package:
ppp
Source:
ppp
Description:
Point-to-Point Protocol (PPP) - daemon
Submitter:
Eckhart Wörner
Date:
2023-11-04 00:21:03 UTC
Severity:
important
#514274#5
Date:
2009-02-05 21:37:01 UTC
From:
To:
With a UMTS connection to o2 Germany, connections sometimes dropped. Looking into that issue with wireshark, I found out that the
connection drops because a TCP package of length 187 + k * 240 bytes (with k in 0,1,...) never makes it to the TCP stack of the
receiver (i.e. the computer where PPP is running). This can be reproduced using netcat and a 187 byte file.
Analyzing the ppp recording itself using wireshark there are three ppp frames displayed for that TCP packet: one frame of length 240,
one frame of length 241 and one frame of length 1.
I wasn't able to reproduce this bug using Windows, however I only tried it with a 187 byte packet, I did not run extensive tests
with variable packet sizes yet.

The used device is a
Bus 004 Device 005: ID 12d1:1003 Huawei Technologies Co., Ltd. E220 HSDPA Modem / E270 HSDPA/HSUPA Modem
#514274#10
Date:
2023-11-04 00:19:36 UTC
From:
To:
Are you still able to reproduce this issue?