I help out with a small office (5 users, currently connected to a Server 2008 R2 DC). In the past month, one of the users has begun to intermittently have times when she cannot browse the internet. The pages 'time out' (her words, I am not at the site during the day). Rebooting doesn't seem to help-- the problem just resolves itself after a period of time and she is able to begin browsing again. During these times, there are no entries logged in the event log. It doesn't appear to be a network connectivity issue, at least from the workstation's point of view. There are also no associated errors logged into the server during these times.
She is using IE 8.0 on an XP Pro SP3 machine, connected to a Server 2008 R2 domain. There is a Cisco ASA 5505 Firewall (licensed for 10 users) acting as the firewall and gateway for the office. DNS is supplied by the DC. I have the workstation set to static networking.
We have been making some changes in the past two months, and the timing of the changes to the beginning of her browsing problems makes me suspicious, but I can't find any concrete evidence anywhere.
6 months ago - network was on an SBS2003 server, using the ISA firewall packaged with SBS. We uninstalled ISA from the server and installed a hardware firewall as the new gateway for the domain. I removed the ISA clients from the workstations, reset their proxy information on each client's browser, and pointed the client gateway's to the new ASA 5505. The ASA has a 10 user license, and we have 6 pc's, 1 server, and two printers which have gateways configured, for a total of 9 nodes. Everything seemed fine at this point.
2 months ago - installed an additional server on the network to begin the transition from SBS 2003 to a Server 2008 DC. Now have a total of 10 nodes on the network. No issues reported.
1 month ago - transitioned to the Server 2008 DC. Migrated files to new server, performed the transition according to MS guides. Server 2008 is now acting DC, and SBS 2003 is decommissioned. Client workstations are now pointed to the Server 2008 for their DNS information (and DHCP where appropriate). It was somewhere in this time period that this one workstation began to intermittently have problems.
An important note is the fact that it is only this one workstation that is experiencing browsing problems. The others are unaffected.
Because there are no network connectivity errors being logged into the client's event viewer, my initial thought is that I had some sort of 'rogue' device trying to access the internet from time to time, and we were exceeding our license count on the ASA. I uninstalled the gateway information from the two printers to be safe, which gets me down to 8 nodes on the network... but she is still having issues.
Even though there are no DNS errors being logged in the DC, I thought that we were possibly having some sort if intermittent DNS resolution issue on the workstation, so my next step was to remove the dynamic addressing from the client and statically set the IP, gateway, and DNS information. Still intermittently having issues.
The last thing I have tried was adding an external DNS server to the client DNS list. The preferred DNS server is the DC, the secondary is the external DNS server from ATT. Still having issues.
At this point, I am stumped. Does anyone have any thoughts on how I would go about resolving the issue?