Help me help the machines talk!
December 14, 2012 12:58 PM Subscribe
Networking filter: I'm a young (still learning much) SysAdmin for a pretty large site. I inherited the network configuration, and now I'm trying to troubleshoot some strange issues: workstations losing connectivity without rhyme or reason, and slow web browsing.
We are having issues with some workstations on our domain losing connection to servers on the domain. We are also having issues browsing the web efficiently – pages load quickly after a 4-6 second delay.
The configuration is as follows:
- Cable Modem connected directly to Hardware Firewall
- Hardware Firewall – set as the Router / Primary Gateway
- Domain Controller – set as the DNS for the domain (running DNS and DHCP)
- Member Servers (4x) – each with a static IP, no DNS or DHCP roles
- 3x gigabit network switches (unsure of the config, done before my time at the site)
- Workstations – we have approx 90 workstations that get IPs from DHCP on the DC
The DHCP scope is set from 126.96.36.199 to 188.8.131.52. Devices with static IP are outside of the DHCP range. Some devices have DHCP reservations.
Domain resolution is slow in web browsers on client PCs. Seems to be an issue with DNS, because after about 4-6 seconds of stall time everything loads very quickly. If I run ipconfig /all on a client PC, I see the primary gateway as the firewall IP, and the DNS as the domain controller IP.
On the Domain Controller, for the active NIC, DNS is set manually to the DNS provided by the ISP.
Forwarding zone on the domain controller is set with the ISP DNS IPs and Google’s DNS IPs.
On the hardware firewall, DNS is set to the ISP DNS IPs.
How can I troubleshoot? Are there error logs I can check to diagnose our network issues? Are there common points of failure I can check? Might this be an issue with our network switches?
Thanks MeFi! I much appreciate the help.