The nxcomp component version 3.0.0  up to 3.5.0 supports options listed below. 

If you need to specify an extra option for nxcomp, you can do this by editing the ProxyExtraOptions key in the /usr/NX/etc/node.cfg configuration file.

link=s    
An indication of the link speed that is going to be used between the proxies. Usually the compression and the other link parameters depend on this setting.
The value can be either 'modem', 'isdn', 'adsl', 'wan', 'lan', 'local' or a bandwidth specification, like for example '56k', '1m', '100m', etc.
                
type=s     
Type of session, for example 'windows', 'unix-kde', 'unix-application', etc.

display=s       
Specify the real display where X connections have to be forwarded by the proxy running on the client.

listen=n
Local port used for accepting the proxy connection.
     
accept=s        
Name or IP of host that can connect to the proxy.
     
connect=s      
Name or IP of host that the proxy will connect to.
     
port=n              
Remote port used for the connection.
     
retry=n             
Number of connection atempts.
     
root=s              
The root directory for the session. Usually is the C-* or S-* in the .nx directory in the user's home, with '*' being the virtual display.
     

session=s       
Name of the session file. The default is the name 'session' in the session directory.
    
errors=s           
Name of the log file used by the proxy. The default is the name 'errors' in the session directory.
     

stats=s             
Name of the file where are written the proxy statistics. The default is a file 'stats' in the session directory. The proxy replaces the data in the file whenever it receives a SIGUSR1 or SIGUSR2 signal:
     
    SIGUSR1   
    Gives total statistics, i.e. statistics collected since the beginning of the
    session.
       
    SIGUSR2   
    Gives partial statistics, i.e. statistics collected since the last time this
    signal was received.
     
cookie=s         
Use the provided cookie for authenticating to the remote proxy. The same cookie is used as the fake value used for the X authorization. The fake cookie is replaced on the X server side with the real cookie to be used for the display, so that the real cookie doesn't have to travel over the net. When not using a proxy cookie, any host will be able to connect to the proxy. See also the 'accept' parameter.
     
nodelay=b       
A boolean indicating if TCP_NODELAY has to be set on the proxy link. Old Linux kernels had problemswith handling TCP_NODELAY on PPP links.
     
policy=b          
Let or not the agent decide when it is the best timeto flush the proxy link. If set to 0, the proxy will flush any encoded data immediately. The option has only effect on the X client side proxy.
     
render=b        
Enable or disable use of the RENDER extension.
     
taint=b             
Try to suppress trivial sources of X roundtrips by generating the reply on the X client side.
     
delta=b            
Enable X differential compression.
     
data=n             
Enable or disable the ZLIB data compression. It is possible to specify a value between 0 and 9. Usually the value is chosen automatically based on the
requested link setting.
       
stream=n       
Enable or disable the ZLIB stream compression. The value, between 0 and 9, is usually determined according to the requested link setting.
     
limit=n             
Specify a bitrate limit allowed for this session.
     
memory=n     
Trigger memory optimizations used to keep small the size of X buffers. This is useful on embedded platforms, or where memory is scarce.
     
cache=n         
Size of the in-memory X message cache. Setting the value to 0 will disable the memory cache as well as the NX differential compression.
     
images=n      
Size of the persistent image cache.
     
shseg=n         
Enable the use of the MIT-SHM extension between the NX client proxy and the real X server. A value greater than 1 is assumed to be the size of requested
shared memory segment. By default, the size of the segment is                          determined based on the size of the in-memory cache.
     
load=b      
Enable loading a persistent X message cache at theproxy startup.
     
save=b      
Enable saving a persistent X message cache at the end of session.
     
cups=n      
Enable or disable forwarding of CUPS connections, by listening on the optional port 'n'.
     
aux=n       
Enable or disable forwarding of the auxiliary X channel used for controlling the keyboard. The 'keybd=n' form is accepted for backward compatibility.
     
smb=n       
Enable or disable forwarding of SMB connections. The 'samba=n' form is accepted for backward compatibility.
     
media=n     
Enable forwarding of audio connections.
     
http=n      
Enable forwarding of HTTP connections.
     
font=n      
Enable forwarding of reversed connections to a font server running on the NX server.
     
file=n      
Enable forwarding of file transfer connections.
     
mask=n      
Determine the distribution of channel ids between the proxies. By default, channels whose ids are multiple of 8 (starting from 0) are reserved for the NX client side. All the other channels can be allocated by the NX server side.
     
timeout=t   
Specify the keep-alive timeout used by proxies to determine if there is a network problem preventing communication with the remote peer. A value of 0                   disables the check.
     
cleanup=t   
Specify the number of seconds the proxy has to wait at session shutdown before closing all channels. The feature is used by the NX server to ensure that services are disconnected before shutting down the link.
     
pack=s      
Determine the method used to compress images.
     
product=s   
The product id of the client or server. The value is ignored by the proxy, but the client or server can provide it to facilitate the support.
     
core=b
Enable production of core dumps when aborting the proxy connection.
     
options=s   
Specify an additional file containing options that has to be merged with option read from the command line or the environment.
     
kill=n     
Add the given process to the list of daemons that must be terminated at session shutdown. Multiple 'kill=n' options can be specified. The proxy will     send them a SIGTERM signal just before exiting.
     
strict=b
Optimize for responsiveness, rather than for the best use of all the available bandwidth.
     
encryption=b
Should be set to 1 if the proxy is running as part of a program providing encryption of the point to point communication.