ZyXEL Communications P-335WT Manual de usuario descargar pdf (Pagina 16)

A.3 Linksys

A.3.1 WRT54G and WRT54GS

model ﬁrmware device NAT bug

WRT54G v2.2 3.03.9 wireless gateway/router yes

WRT54G v2.2 4.20.7 wireless gateway/router yes

WRT54G v2.2 4.20.8 wireless gateway/router yes

WRT54GS v1.0 2.09.1 wireless gateway/router yes

WRT54GS v1.0 4.70.6 wireless gateway/router yes

The WRT54G is a wireless gateway with built-in router, which is based on Linux

and uses the Broadcom UPnP implementation. This implementation – at least in all

versions of the ﬁrmware that were tested – is ﬂawed because the InternalMachine

parameter to AddPortMapping is not checked before a port mapping is established.

If InternalMachine points to a machine that’s not on the internal network, IP

packets will still go through NAT and have their IP header rewritten, so it seems

all traﬃc comes from the router.

Linksys was notiﬁed in early february and acknowledged the bug. A new ﬁrmware

with a ﬁx was not yet publicly available before the deadline for this paper.

A.3.2 BEFW11S4

model ﬁrmware device NAT bug

BEFW11S4 v4 1.45.3 wireless gateway/router no

BEFW11S4 v4 1.52.02 wireless gateway/router no

The BEFW11S4 displays some interesting behaviour. First if all, the scripts as

described in this paper do not seem to work at all. Even requesting a “normal”

portmapping (to the requesting machine itself) does not work.

When a list of existing portmappings is asked with the GetGenericPortMappingEntry

SOAP action, it only returns one portmapping over and over again, namely the

mapping that’s already preset in the device for FTP. No matter wat value of the

NewPortMappingIndex to GetGenericPortMappingEntry is taken, the result is al-

ways the same.

Another bug with the same SOAP action only manifests itself in the 1.45.3 ﬁrmware,

but not in the 1.52.0.2 ﬁrmware. When in a short period of time (several seconds)

a large list of portmappings is requested, the router overloads and drops all connec-

tions to the outside, but the internal switch module still seems to work. Ethereal

shows TCP retransmissions, TCP out of order and duplicate ACKs packets.

import os

from SOAPpy import *

endpoint = "http://192.168.1.1:2468/WANIPConnection"

soapaction = "urn:schemas-upnp-org:service:WANIPConnection:1#GetGenericPortMappingEntry"

i=0

This is not true anymore. Starting with hardware revision 5 of the WRT54G Linksys has

chosen to use VxWorks. The motherboard has much less memory and RAM than previous versions.

However, a new version, the WRT54GL, is nearly identical to previous versions, and is targeted

for people who want to modify their router.

1 2 ... 11 12 13 14 15 16 17 18

Comentarios a estos manuales

Sin comentarios

ZyXEL Communications P-335WT Manual de usuario Pagina 16

Comentarios a estos manuales

Relacionado con productos y manuales para Redes ZyXEL Communications P-335WT