In our office we are several users (ca. 5) that regularly connect to a remote network via VPN. Usually this works fine and has worked fine for years, but recently we have had trouble when more than one or two people connect simultaneously. When an additional user connects, somebody's or everybody else's connection drops. The limit of users seems to vary, going from 1 to 4 maximum simultaneous connections.
The remote VPN host regularly has dozens of simultaneous connections from us as well as other partners. Their network specialists say that the problem must be on our side, since this has not been reported by any other partners.
We regularly connect do a dozen other networks via VPN without any trouble. This however is the only network that might have more than ca. 3 simultaneous connections from us.
We use the Cisco Systems VPN Client V.5.
Where should we start troubleshooting this problem?