You could make a script like that (I suppose the format of your IPs file is 00112233445566 172. 1. 1.254). This is supposed to work only with W95 (I didn't test it).
OPEN(1,"YourIPfile.txt",2)
:LOOP
$X=READLINE(1)
IF $X=""
GOTO END
ENDIF
IF @ADDRESS=SUBSTR($X,1,12) AND @IPADDRESS0<>SUBSTR($X,14,28)
WRITEVALUE("HKEY_LOCAL_MACHINE\TheKeyWhereWindows95StoreTheIP","TheSubkey",SUBSTR($X,14,28,"REG_SZ")
ENDIF
GOTO LOOP
:END
CLOSE(1)

Good luck!