I am having internal network speed issues on my network. The Server (Windows 2008 R2) has two network cards. One provides 802.1x authentication to the outside world. The second, shares this using ICS to other devices on the internal network. The server also acts as a DNS and DHCP Server (DNS primary is set to my server, secondary is that of the external network.
All these devices are connected to a TP-Link TL-SG2109WEB Gigabit managed switch, with 80.211q VLANs – The server and Wireless AP are in both VLANS because the Wireless has multiSID VLANs.
The main problem, as soon as I power the server, the network speed immediately begins to drop within the internal network, within 5 minutes the transfer speed of anything internally is ~100kbs/s when at the beginning its over 50MB/s.
All NICs on the networks are 10/100/1000, so I know that is not the issue.
Solutions tried so far:
- Alternative unmanaged switch
- Different CAT6 cables
- Removing network devices
Any ideas anyone can throw at me would be much appreciated.
EDIT 1 - additional info
I should have also mentioned that sometimes (often after several successive reboots of the entire "internal" network, including server) the internal netowrk works fine, with all transfers above 50MB/sec
EDIT 2 - MTU Changes
Changing the MTU down to 800 on both server and computers failed to solve the problem.