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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

2432.0. "Change Subnet Mask - How To?" by POBOX::ELARSON () Tue Jun 27 1995 14:44

    How do you change the subnet mask on a 900TM?  My customer has a class
    B network and after inputting the IP address, the submask defaulted to
    255.255.255.0.  Is this the correct subnet mask, or should it default
    to 255.255.0.0?  He thinks 255.255.255.0 is causing some traffic problems 
    on his network.  Is this assumption correct?  
    
    I've looked through the menu screens via the setup port and through
    Hubwatch but have come up empty.  Any help is appreciated.
    
    Ed     
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2432.1mask firstHERON::virenq.vbo.dec.com::HEMMINGSLanterne RougeMon Jul 10 1995 09:0015
The only way I have found to do this is to remove the IP address first and 
then reset the mask.  Setting the IP address via the console port appears to 
be available only as a DEFINE command, so the procedure I have used is -

Local>set priv
Password>system
Local def inter addr NONE
Local>init from flash delay 0
...
...
Local>change inter mask 255.255.0.0
Local>change inter addr 1.2.3.4

The order seems to be sensitive, no doubt the terminal server conference has 
some explanation.  You could just reset to factory and start again.
2432.2Mask first, unless its a DEFINE/REBOOT.TOOK::D_NELSONDave Nelson LKG1-3/A11 226-5358Mon Jul 10 1995 13:3522
    RE: .1
    
    I guess we are assuming that "900TM" in .0 means DS900TM.  The order of
    setting net mask and address is important if you are SET'ing or
    CHANGE'ing them.  In that case, do the net mask first.  The order is
    unimportant if you are DEFINE'ing them.  You do _not_ need to go through
    the two-step process you describe in .1 to change the net mask.  Simply
    DEFINE it they way you want and reboot (once).
    
    RE: .0
    
    What the original post seems [to me] to be asking is whether the
    algorithm that imputes a default net mask from the address, when no
    explicit net mask is specified, is performing correctly.  I have not 
    seen a case where it doesn't, but...  BTW, you didn't tell us what the 
    address actually was.
    
    Regards,
    
    Dave
    
    
2432.3What's your starting point?HERON::virenq.vbo.dec.com::HEMMINGSLanterne RougeTue Jul 11 1995 03:227
re -.1 This is what I found out -

If you already have an IP address and a mask, then you cannot SET or 
CHANGE the address or the mask to another value. (message - IP address 
already set).  You cannot SET IP ADDR NONE either.  The only way I have 
succeeded is to DEF IP ADDR NONE and reboot, then you restart with the mask 
first.  It's not a great inconvenience, just one of those things.
2432.4DR900TM, not DS900TMPOBOX::ELARSONTue Jul 11 1995 12:4310
    Thank you all for your input... Perhaps I should've been more specific. 
    It is a DECrepeater 900TM that needs the subnet mask verified to it's
    default of 255.255.0.0.
    
    Is this possible??  
    
    Ed
    
    P.S.  I've had to change the DS900TM and noticed the order of inputting
    mask info first.  :-}
2432.5Just to clarify the point I was making...TOOK::D_NELSONDave Nelson LKG1-3/A11 226-5358Tue Jul 11 1995 15:3921
    RE: .3              
    
    > If you already have an IP address and a mask, then you cannot SET or 
    > CHANGE the address or the mask to another value. 
    
    Correct.  But you _can_ DEFINE the address and net mask to be anything 
    you want, even if the address and net mask have already been SET or
    CHANGE'd.  Beleive me.  I'm the Technical Lead for the DECservers, so I
    have reason to know.
    
    > The only way I have succeeded is to DEF IP ADDR NONE and reboot, then 
    > you restart with the mask first.  It's not a great inconvenience, just 
    > one of those things.
    
    You're going way 'round Robin Hood's barn.  You only need to do the
    DEFINE command and the reboot.  No need to DEF IP ADDR NONE.
    
    Regards,
    
    Dave
      
2432.6I've gone Scarlett (Will, not O'Hara)HERON::virenq.vbo.dec.com::HEMMINGSLanterne RougeWed Jul 12 1995 10:519
>>>    You're going way 'round Robin Hood's barn.  You only need to do the
>>> DEFINE command and the reboot.  No need to DEF IP ADDR NONE.

All my French neighbours say "Ah Robin des Bois" when they get my name, so 
I'm not offended .... (this is French for Robin Hood).

You're right of course, you can do DEFINE and reboot.  When I find a way that 
works, I tend to stick to it.