lammert - 3:02 am on Jan 16, 2008 (gmt 0)

First of all a warm welcome to WebmasterWorld!

This is not really the type of post we expect here of a first time poster, but it is really appreciated :)

Makes me think of a firewall issue. You can program the iptables firewall under Linux in such a way that high speed bursts are allowed, but as soon as people start downloading large amount of data, the number of packets per second is limited. After the server is restarted the counters of the firewall are reset to zero, and high speeds are allowed initially.

You can look at your current rules in the iptables firewall with the following command (with root permissions):

iptables -n -L -v

If there are any IPs or IP ranges in the table that match IPs in the route to Comcast, that might be the reason of your problem.

Also look at netstat -nt when the problem happens to see if the connection states for the comcast users are different from that of other users.