RE: strange network problems

["Kenneth Goodwin" <kgoodwin datamarktech com>]

1. A P2-350 is certainly powerful enough to saturate a 10 mbps cable modem link. You are
probably running out of TCP/IP buffers as a result. Esp since you are uploading to someone else.

2. I dont know the kernel tweak parameters, perhaps others can suggest the right ones,
but things I would try -

Increase number of IO buffers available for network connections. Your Local firewall FTP program is
probably exhausting the pool and TCP/IP buffers dont get released immediately after use, have to wait
for TTL's to expire.

Find a way to decrease your local priority overall (NICE the process) to allow more cpu cycles and resources to external pc's.

try to limit the percentage of the IP IO buffer pool available to each process.

 

Kenneth Goodwin
Director of IT Operations
Datamark Technology, Inc.


>>> -----Original Message-----
>>> From: enigma-list-admin redhat com
>>> [mailto:enigma-list-admin redhat com]On Behalf Of Avery Pierce
>>> Sent: Tuesday, October 29, 2002 11:21 PM
>>> To: enigma-list redhat com
>>> Subject: strange network problems
>>> 
>>> 
>>> Im using a PII 350 with 2 SMC 1211TX Nics (realtek 8139).  
>>> Its used for a firewall / NAT Gateway with 1 pc behind it.  
>>> If im uploading a file on the firewall my pc behind the 
>>> firewall had no internet access on tiemouts.  I get heavy 
>>> packet loss when I ping an outside server..like google.com. 
>>>  When uploading from my pc through the firewall everything 
>>> works just fine.  Downloading also works fine.  Im logging 
>>> all dropped packets with iptables and nothing is behind 
>>> dropped.  There isnt any errors in /var/log/messages 
>>> pertaining to the network interfaces.  ive tried updating 
>>> anything that might be causing this.
>>> 
>>> System:
>>> Redhat 7.2 Enigma
>>> Kernel 2.4.18-17.x
>>> Nic Driver 8139too 
>>> iptables 1.2.5-3
>>> 
>>> I connect to the internet with a SurfBoard sb4100 
>>> cablemodem through Adelphia.
>>> My pc connects to the firewall using a crossover cable.  My 
>>> pc has an smc 1211tx nic also.
>>> Any ideas would be appreciated.  Thanks in advance.
>>> 
>>> Heres an ifconfig on the firewall
>>> 
>>> eth0      Link encap:Ethernet  HWaddr 00:E0:29:1D:98:6E 
>>>           inet addr:192.168.200.1  Bcast:192.168.200.255  
>>> Mask:255.255.255.0 
>>>           UP BROADCAST RUNNING MULTICAST  MTU:1500 Metric:1 
>>>           RX packets:35202 errors:6 dropped:0 overruns:0 frame:0 
>>>           TX packets:24688 errors:0 dropped:0 overruns:0 carrier:0 
>>>           collisions:0 txqueuelen:100 
>>>           RX bytes:2402686 (2.2 Mb)  TX bytes:2912915 (2.7 Mb) 
>>>           Interrupt:5 Base address:0xc000 
>>>  
>>> eth1      Link encap:Ethernet  HWaddr 00:E0:29:95:60:60 
>>>           inet addr:X.X.X.X  Bcast:255.255.255.255  
>>> Mask:255.255.255.0 
>>>           UP BROADCAST NOTRAILERS RUNNING  MTU:1500  Metric:1 
>>>           RX packets:26893 errors:0 dropped:0 overruns:0 frame:0 
>>>           TX packets:35608 errors:0 dropped:0 overruns:0 carrier:0 
>>>           collisions:0 txqueuelen:100
>>>          RX bytes:3045857 (2.9 Mb)  TX bytes:2968880 (2.8 Mb) 
>>>          Interrupt:10 Base address:0xe000 
>>> 
>>> Avery Pierce
>>> Camteq Professional Systems
>>> www.camteq.com
>>> 
>>> 
>>> 
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