I have a leased line which is capped @ 10mbit/sec up & down. Border device is a Draytek Vigor 3300V+. I have a couple of Dell servers running Windows 2003 behind the Draytek. My issue is that the upstream speed from the servers maxes out at about 7-8mbps when accessing them from another location. As a test, I installed Ubuntu on a laptop & stuck it along side the two servers. I ran the same tests from that machine, and the upstream was a steady 10mbps as you'd expect. I've run both iperf and http tests, with the same results. If I access the machines locally, it's nice and fast as you'd expect on a LAN. They just seem to be unable to effectively make use of the 10mbps bandwidth available to them on the leased line. I've tried all sorts of things in an attempt to diagnose what could be the issue affecting the Windows machines, but without any luck. Here's some of the things I've tried...
- Updating network drivers
- Disabling/enabling various advanced settings on the NICs
- Running Wireshark traces and seeing if I can spot any obvious problems
- Latest firmware on the Draytek
- Ruling out any other network equipment (switches, cables)
A few more details that might be relevant:
- Both servers are Dell PowerEdge 2800 machines
- Both run Windows 2003 Server (SBS Edition & Standard Edition) R1
- Both machines have Intel Pro 1000 MT Dual Port adapters
My networking knowledge really isn't up to scratch to diagnose this problem easily. I'm busy brushing up on my low level network in the hope of being able to draw more from the Wireshark traces that I have. Any thoughts of anything else I could try would be very much appreciated.