The problem is that sometimes my webbrowser does not display the requested page. I can also not reach my ISP's pop server sometimes. When this happens i can still ping ip adresses on the internet so the gateway is open.
I was thinking that if i could add some external nameserver adresses maybe the problem was solved.
when you install the SME server the instalation procedure is asking you for the ip adress, netmask, gateway and nameserver adresses. In my case my sme server is behind a firewall. This firewall is owned and administered by the isp who is in the same building as me. Maybe i have to look for the course of this problem in their firewall configuration.
Regards,
P.v.S.