OS: CentOS 5.0 x86.
Hi, I am using CentOS 5.0 at home, ADSL ~16 Mbps/~1 Mbps Internet connection and my ping time to my ISP is 160-170 msec.
When downloading something with Firefox, I am getting download speeds of about 100-180 KB/sec (for example when downloading SP2 of XP from MS server).
Are the CentOS networking settings OK for this kind of latency, or do I have to change some settings?
Thanks in advance.
On Mon, 5 Nov 2007, Ioannis Vranos wrote:
OS: CentOS 5.0 x86.
Hi, I am using CentOS 5.0 at home, ADSL ~16 Mbps/~1 Mbps Internet connection and my ping time to my ISP is 160-170 msec.
When downloading something with Firefox, I am getting download speeds of about 100-180 KB/sec (for example when downloading SP2 of XP from MS server).
Are the CentOS networking settings OK for this kind of latency, or do I have to change some settings?
I am using this on my CentOS 4 machine. I would expect it to work on a CentOS 5 machine as well.
Add the following to /etc/sysctl.conf
net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864
Run sysctl -p
Barry
Barry Brimer wrote:
On Mon, 5 Nov 2007, Ioannis Vranos wrote:
OS: CentOS 5.0 x86.
Hi, I am using CentOS 5.0 at home, ADSL ~16 Mbps/~1 Mbps Internet connection and my ping time to my ISP is 160-170 msec.
When downloading something with Firefox, I am getting download speeds of about 100-180 KB/sec (for example when downloading SP2 of XP from MS server).
Are the CentOS networking settings OK for this kind of latency, or do I have to change some settings?
I am using this on my CentOS 4 machine. I would expect it to work on a CentOS 5 machine as well.
Add the following to /etc/sysctl.conf
net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864
Run sysctl -p
Barry _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
You may want to consider adding QoS to ACKs. Giving ACKs higher priority will allow you to better utilize the link by ensuring they don't get overrun with other traffic. I do this on my OpenBSD firewall with great success.
James A. Peltier wrote:
Barry Brimer wrote:
On Mon, 5 Nov 2007, Ioannis Vranos wrote:
OS: CentOS 5.0 x86.
Hi, I am using CentOS 5.0 at home, ADSL ~16 Mbps/~1 Mbps Internet connection and my ping time to my ISP is 160-170 msec.
When downloading something with Firefox, I am getting download speeds of about 100-180 KB/sec (for example when downloading SP2 of XP from MS server).
Are the CentOS networking settings OK for this kind of latency, or do I have to change some settings?
I am using this on my CentOS 4 machine. I would expect it to work on a CentOS 5 machine as well.
Add the following to /etc/sysctl.conf
net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864
Run sysctl -p
Barry _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
You may want to consider adding QoS to ACKs. Giving ACKs higher priority will allow you to better utilize the link by ensuring they don't get overrun with other traffic. I do this on my OpenBSD firewall with great success.
Yes you are right, we should prioritize ack's and dns requests (port 53) at first. But this is CentOS not BSD, so we should use tc (show / manipulate traffic control settings).
Ioannis Vranos: You should connect from a windows machine and check if the ping reply and the download speeds are the same as on the linux machine. If the windows machine proves to be faster, start debugging the linux machine. 160-170 ms to your ISP's gateway seems a lot of latency to me. I have a cable modem and an 6 ms latency to my ISP.
Bazy wrote:
Yes you are right, we should prioritize ack's and dns requests (port 53) at first. But this is CentOS not BSD, so we should use tc (show / manipulate traffic control settings).
Sorry, as I've said before I'm not familiar with the GNU/Linux equivalent firewall things. Thanks for pointing out TC.
Ioannis Vranos: You should connect from a windows machine and check if the ping reply and the download speeds are the same as on the linux machine. If the windows machine proves to be faster, start debugging the linux machine. 160-170 ms to your ISP's gateway seems a lot of latency to me. I have a cable modem and an 6 ms latency to my ISP.
You may also want to run a netstat -ia on both machines and verify that there are not a bazillion connections, which might give an indication of a system compromise such as rootkit or botkit. 160-170ms seems awful high to me for such a high speed connection.
James A. Peltier wrote:
I am using this on my CentOS 4 machine. I would expect it to work on a CentOS 5 machine as well.
Add the following to /etc/sysctl.conf
net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864
Run sysctl -p
Barry
You may want to consider adding QoS to ACKs. Giving ACKs higher priority will allow you to better utilize the link by ensuring they don't get overrun with other traffic. I do this on my OpenBSD firewall with great success.
How can I do this in CentOS 5.0?
I am using this on my CentOS 4 machine. I would expect it to work on a CentOS 5 machine as well.
Add the following to /etc/sysctl.conf
net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864
Run sysctl -p
Barry
How can I change Time To Live (TTL) in Centos 5.0 x86?
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Barry Brimer -
Bazy -
Ioannis Vranos -
James A. Peltier