OK, I am going to try to keep the details in this first post light, because I am not sure which direction it will go. So, be sure to ask for details if you need them. If anything I explain about the way this used to be setup seems screwy (and it is), I didn't set it up that way, I inherited it.
I manage a third party's windows 2003 domain that is split across two floors (and two IP address ranges) and they communicated over separate ISPs through a VPN. This was because their traffic wasn't allowed on our network and there wasn't any extra fiber to connect the two switches. This was expensive and slow so I decided to setup a VLAN through our network (rules have changed now - they can be on our network) for the two switches to connect. The network equipment are Dell 2724 copper switches, connected to a Dell 6024F with fiber. The VLAN trunk was setup and tested for basic TCP/IP connectivity.
So, I took the VPN connection down, re-IPed the network so it was on one range, connected the two halves together through the VLAN and all seemed to be working - DHCP worked correctly, I could get to the internet through the expected path and see all the hosts on both floors of the network. Life is good.
NOT. So, Monday morning, I hear the first floor can't connect to Exchange, but the third floor can. Also, SBM network shares don't seem to be working, UNC paths won't work - basically, RPC seems to be broken. Non-RPC stuff seems to work, as mentioned above, but Outlook connecting to Exchange doesn't. Interestingly, Outlook seems to be able to send email, but not receive it. Workstation and user authentication seems to work fine.
So far, I have gone over my VLAN configuration with a fine tooth comb. I can't seen any place where it might be mis-configured. I double-checked port configuration (speed, duplex) as 'third party' has a different brand of switches. I have physically moved a problem PC to the third floor network and everything works fine. The issues seems to be isolated to the connection between the two halves of the network.
I have used netmon to capture traffic while trying to connect with outlook and SMB. I see a lot of retransmits.
So, I am open to going any direction on this. What am I missing?
David
