I just change that and seems to be working here, here is details: TCPIP.SYS 5.2.3790.3959 HEX mod original 00000148: 1B 26 00000149: 7E 7D 000B85CC: FF 0A 000B85CD: FF 00 000B85CE: FF 00 the first two is the checksum of the file, the others is the limit, if you want to use a smaller limit, you need to calculate the correct checksum again, I use pechksum to calculate it. use wfpreplace to replace it or try to replace it in safe mode (I didn't check if safe mode really work) p.s. sorry for poor english