Random Network Dropouts
Posted on 2011-02-14
I have a really odd issue. I have users who are having issues where certain parts of their network drops out. These suers are setup to grab ip's via DCHP (from a win 2003 server). Some have a reservation setup.
Anyway, after about 10 minutes of being online (say after an Ip release/renew) they loose connectivity to any server that is not in my direct subnet. This includes internet access, access to my web servers in my DMZ (have public IP's, routed by my sonciwall in transparent mode) or to my phone system.
The phone system is a good place to start. My phone system's PBX is at IP 10.10.60.1. My users are in the 192.168.0.xxx subnet. Users connect to the PBX (for unified messaging services) from their PC (the phones themselves live on the 10.10.60.xxx subnet). Now, in my firewall, I have a route setup for all 10.10.60.0 subnet 255.255.255.0 to route to a VLAN on my phone switch (10.10.60.5) of 192.168.0.130.
My users have no problem pinging the 192.168.0.130 port on my phone switch, but can't ping anything in the 10.10.60.xxx. The annoying part, is it is NOT system wide but contained to a specific group of users. I can't be certain if they all are patched into the same switch - I can go back and trace my drops (which I may need to do), but at least 3 users are geographically close to each other, so it's liekly they are.
Now, my users are patched into my Netgear GSM7352S switches, which I have in a 7 member stack. The stack is in a duplex ring connected by add-on modules (CX-4). The vast majority of my users are patched into these 7 switches (I have 3 other switches on the fringe of my network, 2 48 port Ciscos and 1 28 port linksys all patched via fiber.)
So what could be going on here? It's only certain users.