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DHCP Explorer
DhcpExplorer Description
File Size: 534
DhcpExplorer tool allows you to discover DHCP servers on your local subnet or LAN. This is useful for locating servers that are not supposed to be on your network ( rogue DHCP servers ) as well as checking the expected output of known servers. DHCP Explorer broadcasts on the local physical subnet to find available DHCP servers. The tool is designed with a user-friendly interface and is easy to use.
Last update:
OS: Windows 8, Windows 7, Windows Vista, Windows XP
System Requirements: DHCP enabled on network adapter
License: Freeware 
Last Changes: Updated dhcp client
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  Discover DHCP servers on network Nsauditor scan and monitor network for possible vulnerabilities
 
Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol (DHCP) is a client-server networking protocol and uses the same two IANA assigned ports for BOOTP: 67/udp for the server side, and 68/udp for the client side. A DHCP server provides configuration parameters specific to the DHCP client host requesting, generally, information required by the client host to participate on an IP network. DHCP also provides a mechanism for allocation of IP addresses to client hosts. DHCP server is a useful tool that automates the assignment of IP addresses to hundreds of workstations in your network. The server maintains a pool of IP addresses that you use to create scopes. A DHCP scope is a collection of IP addresses and TCP/IP configuration parameters that are available for DHCP clients to lease. The server automatically allocates these IP addresses and related TCP/IP configuration settings to DHCP-enabled clients in the network. The DHCP service leases the IP addresses to clients for a period that you specify when you create a scope. A lease becomes inactive when it expires. Through the DHCP server, you can reserve specific IP addresses permanently for hardware devices that must have a static IP address (e.g., a DNS server). An advantage of using DHCP is that the service assigns addresses dynamically. The service returns addresses that are no longer in use to the IP address pool so that the server can reallocate them to other machines in the network. If not for this service, you would have to manually configure IP for new computers, keep track of IP addresses so that you could reassign addresses that clients aren't using, and reconfigure computers that you move from one subnet to another
Client Configuration Parameters
A DHCP server can provide optional configurations to the client. RFC 2132 defines DHCP options.

List of configurable options and their corresponding numbers:

                                 Data 
  Tag     Name                  Length  Meaning                              
  ---     ----                  ------  -------                              
   0      Pad                      0    None                                 
   1      Subnet Mask              4    Subnet Mask Value                    
   2      Time Offset              4    Time Offset in                       
                                        Seconds from UTC 
   3      Router                   N    N/4 Router addresses                 
   4      Time Server              N    N/4 Timeserver addresses             
   5      Name Server              N    N/4 IEN-116 Server addresses         
   6      Domain Server            N    N/4 DNS Server addresses             
   7      Log Server               N    N/4 Logging Server addresses         
   8      Quotes Server            N    N/4 Quotes Server addresses          
   9      LPR Server               N    N/4 Printer Server addresses         
  10      Impress Server           N    N/4 Impress Server addresses         
  11      RLP Server               N    N/4 RLP Server addresses             
  12      Hostname                 N    Hostname string                      
  13      Boot File Size           2    Size of boot file in 512 byte        
                                        chunks 
  14      Merit Dump File          N    Client to dump and name              
                                        the file to dump it to 
  15      Domain Name              N    The DNS domain name of the           
                                        client 
  16      Swap Server              N    Swap Server addeess                  
  17      Root Path                N    Path name for root disk              
  18      Extension File           N    Path name for more BOOTP info        
  19      Forward On/Off           1    Enable/Disable IP Forwarding         
  20      SrcRte On/Off            1    Enable/Disable Source Routing        
  21      Policy Filter            N    Routing Policy Filters               
  22      Max DG Assembly          2    Max Datagram Reassembly Size         
  23      Default IP TTL           1    Default IP Time to Live              
  24      MTU Timeout              4    Path MTU Aging Timeout               
  25      MTU Plateau              N    Path MTU  Plateau Table              
  26      MTU Interface            2    Interface MTU Size                   
  27      MTU Subnet               1    All Subnets are Local                
  28      Broadcast Address        4    Broadcast Address                    
  29      Mask Discovery           1    Perform Mask Discovery               
  30      Mask Supplier            1    Provide Mask to Others               
  31      Router Discovery         1    Perform Router Discovery             
  32      Router Request           4    Router Solicitation Address          
  33      Static Route             N    Static Routing Table                 
  34      Trailers                 1    Trailer Encapsulation                
  35      ARP Timeout              4    ARP Cache Timeout                    
  36      Ethernet                 1    Ethernet Encapsulation               
  37      Default TCP TTL          1    Default TCP Time to Live             
  38      Keepalive Time           4    TCP Keepalive Interval               
  39      Keepalive Data           1    TCP Keepalive Garbage                
  40      NIS Domain               N    NIS Domain Name                      
  41      NIS Servers              N    NIS Server Addresses                 
  42      NTP Servers              N    NTP Server Addresses                 
  43      Vendor Specific          N    Vendor Specific Information          
  44      NETBIOS Name Srv         N    NETBIOS Name Servers                 
  45      NETBIOS Dist Srv         N    NETBIOS Datagram Distribution        
  46      NETBIOS Node Type        1    NETBIOS Node Type                    
  47      NETBIOS Scope            N    NETBIOS Scope                        
  48      X Window Font            N    X Window Font Server                 
  49      X Window Manager         N    X Window Display Manager             
  50      Address Request          4    Requested IP Address                 
  51      Address Time             4    IP Address Lease Time                
  52      Overload                 1    Overload "sname" or "file"           
  53      DHCP Msg Type            1    DHCP Message Type                    
  54      DHCP Server Id           4    DHCP Server Identification           
  55      Parameter List           N    Parameter Request List               
  56      DHCP Message             N    DHCP Error Message                   
  57      DHCP Max Msg Size        2    DHCP Maximum Message Size            
  58      Renewal Time             4    DHCP Renewal (T1) Time               
  59      Rebinding Time           4    DHCP Rebinding (T2) Time             
  60      Class Id                 N    Class Identifier                     
  61      Client Id                N    Client Identifier                    
  62      Netware/IP Domain        N    Netware/IP Domain Name               
  63      Netware/IP Option        N    Netware/IP sub Options               
  64      NIS-Domain-Name          N    NIS+ v3 Client Domain Name           
  65      NIS-Server-Addr          N    NIS+ v3 Server Addresses             
  66      Server-Name              N    TFTP Server Name                     
  67      Bootfile-Name            N    Boot File Name                       
  68      Home-Agent-Addrs         N    Home Agent Addresses                 
  69      SMTP-Server              N    Simple Mail Server Addresses         
  70      POP3-Server              N    Post Office Server Addresses         
  71      NNTP-Server              N    Network News Server Addresses        
  72      WWW-Server               N    WWW Server Addresses                 
  73      Finger-Server            N    Finger Server Addresses              
  74      IRC-Server               N    Chat Server Addresses                
  75      StreetTalk-Server        N    StreetTalk Server Addresses          
  76      STDA-Server              N    ST Directory Assist. Addresses       
  77      User-Class               N    User Class Information               
  78      Directory Agent          N    directory agent information          
  79      Service Scope            N    service location agent scope         
  80      Rapid Commit             0    Rapid Commit                         
  81      Client FQDN              N    Fully Qualified Domain Name          
  82      Relay Agent Information  N    Relay Agent Information              
  83      iSNS                     N    Internet Storage Name Service        
  84      REMOVED/Unassigned                                                 
  85      NDS Servers              N    Novell Directory Services            
  86      NDS Tree Name            N    Novell Directory Services            
  87      NDS Context              N    Novell Directory Services            
  88      BCMCS Controller Domain Name list                                  
  89      BCMCS Controller IPv4 address option                               
  90      Authentication           N    Authentication                       
  91      REMOVED/Unassigned                                                 
  92      REMOVED/Unassigned                                                 
  93      Client System            N    Client System Architecture           
  94      Client NDI               N    Client Network Device Interface      
  95      LDAP                     N    Lightweight Directory Access Protocol
  96      REMOVED/Unassigned                                                 
  97      UUID/GUID                N    UUID/GUID-based Client Identifier    
  98      User-Auth                N    Open Group's User Authentication     
  99      Unassigned                                                         
  100     REMOVED/Unassigned                                                 
  101     REMOVED/Unassigned                                                 
  102-107 REMOVED/Unassigned                                                 
  108     REMOVED/Unassigned                                                 
  109     Unassigned                                                         
  110     REMOVED/Unassigned                                                 
  111     Unassigned                                                         
  112     Netinfo Address          N    NetInfo Parent Server Address        
  113     Netinfo Tag              N    NetInfo Parent Server Tag            
  114     URL                      N    URL                                  
  115     REMOVED/Unassigned                                                 
  116     Auto-Config              N    DHCP Auto-Configuration              
  117     Name Service Search      N    Name Service Search                  
  118     Subnet Selection Option  4    Subnet Selection Option              
  119     Domain Search            N    DNS domain serach list               
  120     SIP Servers DHCP Option  N    SIP Servers DHCP Option              
  121     Classless Static Route   N    Classless Static Route Option        
          Option 
  122     CCC                      N    CableLabs Client Configuration       
  123     GeoConf Option          16    GeoConf Option                       
  124     V-I Vendor Class              Vendor-Identifying Vendor Class      
  125     V-I Vendor-Specific           Vendor-Identifying Vendor-Specific   
          Information                   Information
  126     Removed/Unassigned                                                 
  127     Removed/Unassigned                                                 
  128     PXE - undefined (vendor specific) (Tentatively Assigned - June 23, 
  128     Etherboot signature. 6 bytes: E4:45:74:68:00:00       
  128     DOCSIS "full security" server IP address      
  128     TFTP Server IP address (for IP Phone software load)   
  129     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  129     Kernel options. Variable length string        
  129     Call Server IP address        
  130     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  130     Ethernet interface. Variable length string.   
  130     Discrimination string (to identify vendor)    
  131     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  131     Remote statistics server IP address   
  132     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  132     802.1P VLAN ID        
  133     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  133     802.1Q L2 Priority    
  134     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  134     Diffserv Code Point   
  135     PXE - undefined (vendor specific) (Tentatively Assigned - 23 Jun 20
  135     HTTP Proxy for phone-specific applications    
  136-149 Unassigned                                                         
  150     TFTP server address (Tentatively Assigned - 23 Jun 2005)
  150     Etherboot     
  150     GRUB configuration path name  
  151-174 Unassigned                                                         
  175     Etherboot (Tentatively Assigned - 23 Jun 2005)
  176     IP Telephone (Tentatively Assigned - 23 Jun 2005)
  177     Etherboot (Tentatively Assigned - 23 Jun 2005)
  177     PacketCable and CableHome (replaced by 122)   
  178-207 Unassigned                                                         
  208     pxelinux.magic (string) = F1:00:74:7E (241.0.116.126) (Tentatively
            Assigned - 23 Jun 2005)
  209     pxelinux.configfile (text) (Tentatively Assigned - 23 Jun 2005)
  210     pxelinux.pathprefix (text) (Tentatively Assigned - 23 Jun 2005)
  211     pxelinux.reboottime (unsigned integer 32 bits) (Tentatively Assigned
            - 23 Jun 2005)
  212-219 Unassigned
  220     Subnet Allocation Option (Tentatively Assigned - 23 Jun 2005)
  221     Virtual Subnet Selection Option       (Tentatively Assigned - 23 Jun 2005
  222-223 Unassigned                                                         
  224-254 Private Use 
  255     End                      0    None
 

Nsauditor scan and monitor network for possible vulnerabilities

Nsauditor Network Security Auditor is a network security scanner that allows to audit and monitor network computers for possible vulnerabilities, checks your network for all potential methods that a hacker might use to attack it. Nsauditor is a complete networking utilities package that includes a wide range of tools for network auditing, scanning, monitoring and more. You can discover network services and check them for vulnerabilities, list all TCP and UDP endpoints with their associated process, discover NetBios names, audit MS SQL servers, scan for common Adware traces and more. The program also includes real-time network packet filtering and analyzing, web proxy scanning, password auditing, IP address lookup and more than 45 network tools for scanning, sniffing, enumerating and gaining access to machines, DNS and WHOIS lookups, e-mail validation, HTTP traffic generator and intrusion detection based on security events log. Reports can be generated in HTML and XML format. Overall, this is a very complete package for a surprisingly low price.

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