[plug] strange modem behaviour under linux

[Benjamin Keith]

Hi list,

I'm having some trouble downloading to my home machine (Kuhal) under
linux.  This machine is a dual boot Win95/Linux (Mandrake  7.0).  Under
Linux it acts as a gateway for another Win95 box (Patch) using ip
forwarding (ipchains).  The problem I am having is that when Kuhal is
booted to Linux any form of downloading (netscape, ncftp, wget, ftp/http
etc) stalls fatally, usually after only a few hundred kb.  When Kuhal is
booted to Win95 I have no problem with any form of downloading.  When
Patch is downloading *through* Kuhal I have no problems.  To me this
would rule out any problem with the connection to my ISP or some fault
in the modem (AcerModem 56 Surf).
Below are some of the network and routing details:

[root at Kuhal bjkeith]# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:40:C7:2D:A6:67
          inet addr:192.168.1.100  Bcast:192.168.1.255
Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:6 dropped:0 overruns:0 carrier:12
          collisions:102 txqueuelen:100
          Interrupt:11 Base address:0xe400

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:3924  Metric:1
          RX packets:487 errors:0 dropped:0 overruns:0 frame:0
          TX packets:487 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0

ppp0      Link encap:Point-to-Point Protocol
          inet addr:202.148.94.1  P-t-P:203.24.97.2
Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:8453 errors:120 dropped:0 overruns:0 frame:120
          TX packets:7597 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10

[root at Kuhal bjkeith]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
255.255.255.255 0.0.0.0         255.255.255.255 UH    0      0        0
eth0
203.24.97.2     0.0.0.0         255.255.255.255 UH    0      0        0
ppp0
192.168.1.100   0.0.0.0         255.255.255.255 UH    0      0        0
eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0
eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0
lo
0.0.0.0         203.24.97.2     0.0.0.0         UG    0      0        0
ppp0

the ipchains line in /etc/rc.d/rc.local is:

# Setting up IP forwarding and Masquerading with ipchains
/sbin/ipchains -A forward -j MASQ -s 192.168.1.0/24 -d 0.0.0.0/0

the ip for Kuhal is 192.168.1.100
using dhcp Patch gets assigned 192.168.1.101

any insights or suggestions would be appreciated.  If any of the above
is unclear or you want/need additional info let me know.

Thanks in advance

Ben

email: bjkeith at cygnus.uwa.edu.au