The main problem I was having was with the syntax of the protocol.ini (and etc.) files, which I finally did get right.
I've got DOS v6.22 logged into a share on an NT4 box now!
Note: I had to upgrade to v6.22 because the himem.sys in v6.21 is poo.
Here is the contents on the relevant system files:
Protocol.iniCODE
[network.setup]
version=0x3110
transport=ms$tcpip,MS$TCPIP
transport=ms$ndishlp.MS$NDISHLP
lana0=DC21X4,1,ms$tcpip
lana1=DC21X4,1,ms$ndishlp
netcard=DC21X4,1,DC21X4,1
[PROTMAN]
DriverName=PROTMAN$
PRIORITY=ms$ndishlp
[MS$NDISHLP]
DriverName=ndishlp$
BINDINGS=DC21X4
[MS$TCPIP]
NBSessions=6
DisableDHCP=0
DriverName=TCPIP$
BINDINGS=DC21X4
LANABASE=0
[DC21X4]
drivername=DC21X4$
ConnectionType=AutoSense
System.iniCODE
[network]
sizworkbuf=1498
filesharing=no
printsharing=no
autologon=yes
computername=DOS622
lanroot=C:\DOS\NETWORK
username=Administrator
workgroup=WORKGROUP
reconnect=yes
dospophotkey=N
lmlogon=0
logondomain=WORKGROUP
preferredredir=full
autostart=full
maxconnections=8
[network drivers]
netcard=DC21X4.dos
transport=tcpdrv.dos,nemm.dos
devdir=C:\DOS\NETWORK
LoadRMDrivers=yes
[386enh]
TimerCriticalSection=5000
UniqueDosPSP=TRUE
PSPIncrement=2
[Password Lists]
*Shares=C:\DOS\NETWORK\Shares.PWL
ADMINISTRATOR=C:\DOS\NETWORK\ADMINIST.PWL
Config.sysCODE
DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\EMM386.EXE NOEMS
BUFFERS=25,0
FILES=40
DOS=HIGH,UMB
LASTDRIVE=Z
FCBS=4,0
rem DEVICE=C:\DOS\EMM386.EXE RAM I=B100-B7FF I=C600-C7FF I=CC00-CFFF I=E600-EFFF FRAME=D000
DEVICE=C:\DOS\NETWORK\IFSHLP.SYS
rem DEVICEHIGH=C:\DOS\VMADD386.SYS
rem DOS=HIGH
REM ======== IDE BUS CD-ROM Install Modification - Begin ========
rem DEVICE=C:\DOS\CDROM.SYS /D:ATAPI_CD
REM ======== IDE BUS CD-ROM Install Modification - End ==========
AutoExec.batCODE
LH /L:0 C:\DOS\SMARTDRV.EXE /X
@ECHO OFF
PROMPT $p$g
PATH C:\DOS\NETWORK;C:\DOS
SET TEMP=C:\DOS
REM ======== IDE BUS CD-ROM Install Modification - Begin ========
rem C:\DOS\MSCDEX /V /D:ATAPI_CD /M:10
REM ======== IDE BUS CD-ROM Install Modification - End ========
LH /L:1,640 C:\DOS\Idle.com
LH /L:0;1,1728;2,28224 /S C:\DOS\NETWORK\net initialize
C:\DOS\NETWORK\netbind.com
CLS
LH /L:0;1,736 /S C:\DOS\NETWORK\umb.com
LH /L:2,77024 C:\DOS\NETWORK\tcptsr.exe
LH /L:0 C:\DOS\NETWORK\tinyrfc.exe
C:\DOS\NETWORK\nmtsr.exe
C:\DOS\NETWORK\emsbfr.exe
LH /L:0;2,304 /S C:\DOS\NETWORK\net start