fw-1 general & VPN questions

From: AC (ac0at_private)
Date: Sun Apr 19 1998 - 21:34:43 PDT

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    Hi folks,
    
    	Currently I am involved in a project which requires that
    I set up a central fw-1 mgmt station, to manage 2 fw-1 (on 
    solaris 2.5.1) boxen via an encrypted VPN over the internet.
    I also intend to do some "out-of-band" mgmt with a dialin
    modem on the serial console of the two sun boxes (yes, yes,
    wardialers I know). However, this is what the customer wants,
    and I have no say-so, so I need to simply get it set up.
    
    A couple general questions about fw-1:
    
    1) Does fw-1 actually *break* the client/server model? Application
       gateways like FWTK actually will generate an entirely new packet
       from the OS IP stack to to handle communication between 
       clients and & external servers. This is a more secure setup,
       IMHO. So, does fw-1 actually *forward* IP packets to 
       internal clients after checking its ruleset? Can I turn this
       off i.e. (ndd /dev/ip stuff?) and the fw-1 still work?
    
    2) Does fw-1 handle fragmented packets correctly? i.e. does it
       handle the reassembly or does the OS IP stack?
    
    3) Concerning NAT: client has a T1 to Net, fw-1-A, and also
       a private point-to-point T1 connection to another company,
       with fw-1-B sitting there. Both fw-1s are doing NAT. 
       Now if an internal client has his default route pointing
       to the internal interface of the fw-1-A, and he wants to
       talk to somebody on the Net, packet hits fw-1-A, internal
       IP gets translated, and out it goes. BUT, if that same
       clients wants to talk to a machine on the other side of
       fw-1-B, he cannot, as his IP has been translated to an 
       external (public) address, and can't get back in. SO
       I have been forced to segregate clients who can talk
       to the internet via fw-1-A, and clients that can 
       talk to other_company via fw-1-B. Is there any way to
       solve this problem nicely? BY putting in appropriate
       routes, I think I can get this to work, but the fw-1-A will
       be putting this packet out on the wire twice, and
       I have to turn on ip forwarding. 
    
    Ok, now a couple VPN-specific questions: I
    
    1) I am going to use DES instead of the proprietary FWZ 
       encryption for the fw-1->fw-1 connection. Any patches 
       or anything I need to know about? Also the licenses
       that I require to make this whole VPN setup work 
       are extremely confusing, checkpoint is as bad as 
       microsoft, nickel and diming you the whole way.
       If anybody knows what licenses I need on the central
       mgmt station, as well as the managed firewalls, I'd
       appreciate it.
    
    2) Which TCP/UDP ports do the "firewall control connections"
       use?
    	a) If this is a known port or range of ports, is it
       	   not possible to launch a denial-of-service 
     	   against a fw-1 being managed by a VPN over the
     	   INternet? i.e. simply flood those ports on 
     	   fw-1, and boom, the mgmt station cant talk to
    	   the firewall its trying to manage.
    	b) On the 2 fw-1s to be managed, I am being forced
    	   to use the GUI interface, as I don't get INSPECT
    	   yet. Now if I check the box "enable firewall-1
     	   control connections" how/where do I specify
    	   a list of IPs to accept control connections
    	   from? or do I install a new rule in the rulebase
    	   for this? I certainly hope that Joe Random
    	   Hacker cant manage my firewalls remotely!
    
    Thanks you for your time and any light you can shed is
    greatly appreciated. If you are in NYC, I'll owe you 
    a brew ;)
    
    --ANindya
    



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