Onsite Network Consulting

To work with networking, a good understanding of IP Addressing and DNS is required.

• Understanding IP Addressing
• Understanding DNS
• Understanding DHCP
• What is my Public IP Address?
• Online IP Subnet Calculator

I have been working as a network engineer since the mid 90's, here are some of the sites I use the most.

Misc. Tools and Links

• Cisco
• DYNDNS
• DNS Stuff
• EditDNS - Free DNS hosting
• Default TTL Values in TCP/IP - Passive Fingerprinting:

  • # OS	     	VERSION	PLATFORM	TTL	WINDOW		DF	TOS
    #---	     	-------	--------	---	-----------	--	---
    
    DC-OSx          1.1-95  Pyramid/NILE    30      8192            n       0
    
    Windows	     	9x/NT	Intel		32	5000-9000	y	0
    
    NetApp  	OnTap   5.1.2-5.2.2     54      8760            y       0
    
    HPJetDirect     ?       HP_Printer      59      2100-2150       n       0
    
    AIX          	4.3.x   IBM/RS6000      60     	16000-16100     y       0
    AIX          	4.2.x   IBM/RS6000      60     	16000-16100     n       0
    Cisco           11.2    7507            60      65535           y       0
    DigitalUnix  	4.0     Alpha		60     	33580		y	16
    IRIX         	6.x     SGI             60     	61320           y       16
    OS390           2.6     IBM/S390        60      32756           n       0
    Reliant         5.43    Pyramid/RM1000  60      65534           n       0
    
    FreeBSD		3.x	Intel		64	17520		y	16
    JetDirect	G.07.x  J3113A		64	5804-5840	n	0
    Linux		2.2.x	Intel		64	32120		y	0
    OpenBSD 	2.x	Intel		64	17520		n	16
    OS/400		R4.4	AS/400		64	8192		y	0
    SCO		R5	Compaq		64	24820		n	0
    Solaris 	8       Intel/Sparc     64      24820           y       0
    FTX(UNIX)       3.3     STRATUS         64      32768           n       0
    Unisys		x	Mainframe	64	32768		n	0
    
    Netware 	4.11	Intel		128	32000-32768	y	0
    Windows		9x/NT	Intel		128	5000-9000	y	0
    Windows 	2000    Intel           128     17000-18000     y       0
    
    Cisco		12.0	2514		255	3800-5000	n	192
    Solaris		2.x	Intel/Sparc	255	8760		y	0	
    
    
    ## ADDITIONAL NOTES
    #
    # Cisco IOS 12.0 normally starts all IP sessions with IP ID of 0
    # Solaris 8 uses a smaller TTL (64) then Solaris 7 and below (255).
    # Windows 2000 uses a much larger Window Size then NT.

Network Monitoring

• SiteUpTime
• SmallNetBuilder
• Zenoss - Open Source Enterprise Monitoring
• Nagios - Open Source Network Monitoring
• Oreon-project - Oreon has become a reference as a Nagios Frontend
• Cacti - Open Source Network Monitoring
• Snort is an open source network intrusion prevention and detection system.
• Nmap - Network exploration and security auditing
• Insecure.org - Network Tools and Hacking Resources
• Network Monitoring Tools
• Computer Network Defence - Very nicely done!

Firewalls

• ClarkConnect
• IPCop
• IPCop - Documentation
• m0n0wall
• m0n0wall Forums
• SmoothWall
• pfSense
• The fastest review EVER of 5 Linux firewall distributions
• More firewall distros
• untangle - Open Source Network Gateway