TCP/IP problems with a Token-Ring/Ethernet bridge
If you cannot communicate between a token-ring and an Ethernet network, using a bridge, and you have verified that the bridge is functioning correctly, the Ethernet adapter might be dropping packets.
A machine drops packets if the incoming packet (including headers) is greater than the network adapter maximum transmission unit (MTU) value. For instance, a 1500-byte packet sent by a token-ring adapter over the bridge collects an 8-byte logical link control (LLC) header, making the total packet size 1508. If the receiving Ethernet adapter MTU is set to 1500, the packet is dropped.
Check the MTU values of both network adapters. To allow for the eight-byte LLL header, the token-ring adapter attaches to outgoing packets, set the MTU value for the token-ring adapter at least eight bytes lower than the MTU value for the Ethernet adapter. For example, set the MTU for a token-ring adapter to 1492 to communicate with an Ethernet adapter with an MTU of 1500.