Hi guys I am writing a serial network driver. My aim is to bridge two ethernets across a serial bridge. Unfortunately the channel is noisy and slip and ppp are too unreliable. The driver appears to work by itself and allows two computers to ping each other across a null modem cable. The network driver code permits Linux OS ARPing support for ethernet and MAC addresses are manually assigned by insmod. The driver is based on mkiss.c: the packet radio driver for serial ttys except that I have eliminated ax25 specific code, interfaced to IP directly and added some ethernet support. Now the problem... The network driver cannot be bridged to an ethernet card using the bridge-utilities layer 2 bridge tools. Note that I have successfully bridged between the ethernet card and other ethernet like hardware such as cisco pci340 WiFi by using these tools. I am using bridge-utilities-0.9.6-1 on linux 2.4.18-14 and linux 2.20-8. Any ideas about what I should include as software support in the driver code that will make bridge-utilities happy? What does bridge-utilities expect to have available to do its job? Cheers Gerard Borg Australian National Univesrity