I have problems with our Internet and LAN performance. There is a backup task that runs every night (8:00 p.m.) using backup exec (symantec) installed in one server, and it retrieves the information from another server which has a remote agent to do the backup task. The remote server has 2 IP addresses, this is a must for an additional application it has.
The thing is, when this task is in progress, everything goes down. The LAN connectivity with our branches (point to point links) is lost and so Internet. I ran wireshark in the server where information is retrieved and saw red coloured packets with this message " header checksum 0x0000, incorrect it should be....". The same backup task is performed in other servers and this don´t happen.
This is the only hint I got so far, I already check our switches, routers, VLAN and everything is normal, I haven´t change nothing recently. Attached you could see a diagram, and according to switch theory this traffic shouldn´t reach our core switch which filters traffic to Internet and branches.
Any advice please, I´m desperating with this problem....