Hi,
I have problem with a Centos 5.3 computer. The networking is very
slow. The networking card is a RealTek 1GigE.
I plugged an Ubuntu laptop on the same cable and port with an Intel
GigE, and it's about 8 to 10 times faster. So the problem is likely to
be with the CentOS config.
Any suggestion on how to track down the problem with speed.
I have checked the packets with wireshark, no problem.
Here's my ethtool eth0 output:
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Here's ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:06:7B:00:14:16
inet addr:192.168.2.103 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::206:7bff:fe00:1416/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3139398 errors:0 dropped:0 overruns:0 frame:0
TX packets:2890605 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4048643591 (3.7 GiB) TX bytes:257250846 (245.3 MiB)
Any suggestion?
--
Thanks
lspci -v output whould be helpful centos at 911networks.com wrote:> Hi, > > I have problem with a Centos 5.3 computer. The networking is very > slow. The networking card is a RealTek 1GigE. > > I plugged an Ubuntu laptop on the same cable and port with an Intel > GigE, and it's about 8 to 10 times faster. So the problem is likely to > be with the CentOS config. > > Any suggestion on how to track down the problem with speed. > > I have checked the packets with wireshark, no problem. > > Here's my ethtool eth0 output: > > Advertised auto-negotiation: Yes > Speed: 1000Mb/s > Duplex: Full > > Here's ifconfig eth0 > > eth0 Link encap:Ethernet HWaddr 00:06:7B:00:14:16 > inet addr:192.168.2.103 Bcast:192.168.2.255 Mask:255.255.255.0 > inet6 addr: fe80::206:7bff:fe00:1416/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:3139398 errors:0 dropped:0 overruns:0 frame:0 > TX packets:2890605 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:4048643591 (3.7 GiB) TX bytes:257250846 (245.3 MiB) > > Any suggestion? > >
ethtool eth0 and lsmod would be helpful as well. centos at 911networks.com wrote:> Hi, > > I have problem with a Centos 5.3 computer. The networking is very > slow. The networking card is a RealTek 1GigE. > > I plugged an Ubuntu laptop on the same cable and port with an Intel > GigE, and it's about 8 to 10 times faster. So the problem is likely to > be with the CentOS config. > > Any suggestion on how to track down the problem with speed. > > I have checked the packets with wireshark, no problem. > > Here's my ethtool eth0 output: > > Advertised auto-negotiation: Yes > Speed: 1000Mb/s > Duplex: Full > > Here's ifconfig eth0 > > eth0 Link encap:Ethernet HWaddr 00:06:7B:00:14:16 > inet addr:192.168.2.103 Bcast:192.168.2.255 Mask:255.255.255.0 > inet6 addr: fe80::206:7bff:fe00:1416/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:3139398 errors:0 dropped:0 overruns:0 frame:0 > TX packets:2890605 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:4048643591 (3.7 GiB) TX bytes:257250846 (245.3 MiB) > > Any suggestion? > >-- Jeff Howell Sr. Linux Administrator Media News Group interactive 303.563.6394 jhowell at medianewsgroup.com
centos at 911networks.com wrote:> Hi, > > I have problem with a Centos 5.3 computer. The networking is very > slow. The networking card is a RealTek 1GigE.Get a better NIC, Realtek is absolute crap. CentOS is an "enterprise grade" OS, use an "enterprise grade" NIC such as Intel or Broadcom. nate
Hi, On Wed, Sep 16, 2009 at 11:25, <centos at 911networks.com> wrote:> I plugged an Ubuntu laptop on the same cable and port with an Intel > GigE, and it's about 8 to 10 times faster. So the problem is likely to > be with the CentOS config.How did you test that? Opening a web page? Downloading a big file?> Any suggestion on how to track down the problem with speed.First check if it's a DNS issue, check your /etc/resolv.conf to see if both DNS servers there are correct, then check with "host" or "nslookup" querying all of them to see if you get replies all of the time. If you have an iptables firewall running, you might want to try to temporarily disable it to see if there is a difference. If it's not DNS or Firewall, you might want to use "iperf" to measure the bandwidth available between that host and another host that works well in your network. You can get "iperf" from the RPMforge repository (http://wiki.centos.org/AdditionalResources/Repositories/RPMForge) or from http://iperf.sourceforge.net/ (binaries for Linux and other platforms should be available). From "iperf" you can really know if there is an actual difference from your CentOS machine to your Ubuntu laptop, with those numbers we might be able to give you better suggestions on how to diagnose your problem. HTH, Filipe