I have run into a very peculiar problem. I have installed Fedora Core 3 on an Athlon64 System (MSI K8Neo Platinum motherboard and an AMD64-3000 cpu). This system has an onboard Gigabit ethernet which is identified by the kernel and operates correctly. I installed the latest asterisk for use as a SIP only server / gateway. There are 5 cisco 7940 IP Phones and codec g729 is used, and a cisco router 3640 is used as a gateway to the pbx via its isdn bri voice lines. One of the problems is that when i try to call a line to the pbx, the network on the linux machines stops almost completely. In the logs (message and dmesg) there are entries NETDEV WATCHDOG: eth0 timeout after a minute the network is restored. This happens only when a place a call to pass thru asterisk to the pbx via the cisco gateway. Also if i put the ethernet in promiscuous mode, it does not hangup. I have not run into a behavior like this one before with 32bit systems (Intel / AMD). Is it a problem of X86_64 or with the onboard ethernet controller? Why it is done only with asterisk? For example FTP works ok with heavy load... Any help will be highly appreciated. Savas Pavlidis