Hello. We are having some trouble with our firewall.
Here goes :
We have a Sonicwall NSA 2400 updated to the latest firmware (SonicOS Enhanced 220.127.116.11-31o) providing internet connectivity to our lan users. However, at random interval, several times per day, we lose internet connectivity for up to a minute each time.
Here is some data we have been gathering :
The ISP doesn't seem to be at fault. we have verified this by splitting up the wan connection two ways to the sonicwall device and to a WRT54G router (each being assigned their own external IP addresses). While experiencing an internet dropout from behind the Sonicwall, users behind the cheap router were still able to surf the net.
Whenever there is a "dropout", it is only new connections to the internet that do not work. Open connections remain open. This has been verified with a number of services (RDP, VPN, http transfers, FTP transfers...). I have been able to keep one such file transfer (throttled) for 4 days without interruption, even while the users were getting internet dropouts
Whenever there is a dropout, the link to the internet is not saturated. We verify this with the Real-Time monitor tool of the firewall's interface that shows about 20% bandwidth usage (incoming or outgoing, or both).
While there is a dropout, pings to the internet won't go through (either to a DNS name or to an IP address)
While there is a dropout, the ping tool from the Sonicwall's System Diagnostics page is unable to ping a target on the internet. When the internet works, we can ping our provider's gateway and the ping time is always lower then 1ms
Any ideas on how to resolve this issue?