[En-Nut-Discussion] disabling NetBIOS wins responder in 3.9.6

William Baker bbaker at priefert.com
Fri May 27 20:56:49 CEST 2005

I installed and ran the httpserv-er from 3.9.6.  When connected to my 
network, communication is very intermittant.  When connected on an 
isolated subnet, communication is clean and reliable.  Here is a simple 
ping log while the device is connected to my primary network.  Notice 
the dropped packets and 3+ sec responses.

64 bytes from icmp_seq=25 ttl=64 time=0.757 ms
64 bytes from icmp_seq=26 ttl=64 time=0.760 ms
64 bytes from icmp_seq=27 ttl=64 time=0.766 ms
64 bytes from icmp_seq=28 ttl=64 time=0.758 ms
64 bytes from icmp_seq=29 ttl=64 time=0.764 ms
64 bytes from icmp_seq=30 ttl=64 time=0.758 ms
64 bytes from icmp_seq=35 ttl=64 time=3698 ms
64 bytes from icmp_seq=43 ttl=64 time=3438 ms
64 bytes from icmp_seq=47 ttl=64 time=0.763 ms
64 bytes from icmp_seq=48 ttl=64 time=0.784 ms
64 bytes from icmp_seq=49 ttl=64 time=0.763 ms

Capturing packets over the network shows that the device is issueing too 
many ARP requests, which appear to be associated with NetBIOS browser 
announcements, ie, the nut/os sends ARP requests each time it sees the 
BROWSER packet.  Here is a sample network capture.  The Ethernut 2.1 
device is IP

     41 14.847438         BROWSER  
Host Announcement POWDERCOAT-XP, Workstation, Server, NT Workstation, 
Potential Browser
     42 14.848502         Broadcast             ARP      
Who has  Tell
     43 15.335182         Broadcast             ARP      
Who has  Tell
     44 16.460034         Broadcast             ARP      
Who has  Tell
     45 16.846605          NBNS     
Registration NB PRIEFERT<1d>
     46 18.585031         Broadcast             ARP      
Who has  Tell
     47 19.022508         Broadcast             ARP      
Who has  Tell
     48 19.470393   Hewlett-_b3:22:80     09:00:09:00:00:67     HPEXT    
U, func=UI; DSAP HP Extended LLC Individual, SSAP HP Extended LLC 
Command; HPEXT; DXSAP 0623, SXSAP 0623
     49 19.594466          Broadcast             ARP      
Who has  Tell
     50 20.337508         NETLOGON 
SAM LOGON request from client
     51 20.675168         Broadcast             ARP      
Who has  Tell
     52 22.531522          Broadcast             ARP      
Who has  Tell
     53 24.662008         Broadcast             ARP      
Who has  Tell
     54 28.022267            NTP      NTP
     55 28.074988         BROWSER  
Host Announcement CEASLEY_ZEBRA, Workstation, Server, Domain Member 
Server, Print Queue Server
     56 28.076031         Broadcast             ARP      
Who has  Tell
     57 28.522581         Broadcast             ARP      
Who has  Tell
     58 29.647425         Broadcast             ARP      
Who has  Tell

It's also strange to see the ARP request sent multiple times.  Hence, it 
appears that both ARP and NetBIOS services exhibit some breakage.

I don't think you can disable ARP and still have a functional server 
TCP/IP device, can you?
Can the NetBIOS Wins responder be disabled?  It does not appear to be 
possible with the configurator.  Can I edit UserConf.mk to add 
parameters to disable this feature?  Where do I find the variables that 
are understood in UserConf.mk?

I regret to say I have no experience with 3.9.5 and cannot currently 
verify its behavior.

Other than that, Nut/OS is really impressive, and I look forward to 
seeing it evolve over the years.


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