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Re^2: How can I find a MAC address from aremote IP ?

by afoken (Parson)
on May 09, 2009 at 15:28 UTC ( #763051=note: print w/ replies, xml ) Need Help??


in reply to Re: How can I find a MAC address from aremote IP ?
in thread How can I find a MAC address from aremote IP ?

Nope, that's not DOS, that's Windows. And it simply does not work. It asks the remote host via Microsoft propritary protocols for its MAC address. Already a simple samba server simply responds with a faked MAC of 00-00-00-00-00-00, and if the host does not respond to MS protocols, it returns "host not found":

Microsoft Windows 2000 Version 5.00.2195
(C) Copyright 1985-2000 Microsoft Corp.

H:\>nbtstat -a enterprise

Local Area Connection:
Node IpAddress: 192.168.1.20 Scope Id: []

           NetBIOS Remote Machine Name Table

       Name               Type         Status
    ---------------------------------------------
    ENTERPRISE     <00>  UNIQUE      Registered
    ENTERPRISE     <03>  UNIQUE      Registered
    ENTERPRISE     <20>  UNIQUE      Registered
    ENTERPRISE     <00>  UNIQUE      Registered
    ENTERPRISE     <03>  UNIQUE      Registered
    ENTERPRISE     <20>  UNIQUE      Registered
    ..__MSBROWSE__.<01>  GROUP       Registered
    XXXXX          <1D>  UNIQUE      Registered
    XXXXX          <1B>  UNIQUE      Registered
    XXXXX          <1C>  GROUP       Registered
    XXXXX          <1E>  GROUP       Registered
    XXXXX          <00>  GROUP       Registered
    XXXXX          <1D>  UNIQUE      Registered
    XXXXX          <1B>  UNIQUE      Registered
    XXXXX          <1C>  GROUP       Registered
    XXXXX          <1E>  GROUP       Registered
    XXXXX          <00>  GROUP       Registered

    MAC Address = 00-00-00-00-00-00


H:\>nbtstat -a galileo7

Local Area Connection:
Node IpAddress: 192.168.1.20 Scope Id: []

    Host not found.

H:\>ping galileo7

Pinging galileo7.xxxxx.xxx 192.168.1.1 with 32 bytes of data:

Reply from 192.168.1.1: bytes=32 time<10ms TTL=64
Reply from 192.168.1.1: bytes=32 time<10ms TTL=64
Reply from 192.168.1.1: bytes=32 time<10ms TTL=64
Reply from 192.168.1.1: bytes=32 time<10ms TTL=64

Ping statistics for 192.168.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum =  0ms, Average =  0ms

H:\>

Reading the ARP cache can help here, but you must have communicated with a host before its MAC is in the ARP cache:

H:\>arp -a

Interface: 192.168.1.20 on Interface 0x1000003
  Internet Address      Physical Address      Type
  192.168.1.1           00-12-17-XX-XX-4e     dynamic
  192.168.1.10          00-08-54-XX-XX-d8     dynamic
  192.168.1.12          00-01-e6-XX-XX-41     dynamic

H:\>

The same trick also works on Linux:

$ /sbin/arp -v
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.20             ether   00:1e:90:XX:XX:c3   C                     br0
galileo7.xxxxx.xxx       ether   00:12:17:XX:XX:4e   C                     br0
Entries: 2      Skipped: 0      Found: 2

$ /sbin/arp -v -n
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.20             ether   00:1e:90:XX:XX:c3   C                     br0
192.168.1.1              ether   00:12:17:XX:XX:4e   C                     br0
Entries: 2      Skipped: 0      Found: 2

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)


Comment on Re^2: How can I find a MAC address from aremote IP ?
Re^3: How can I find a MAC address from aremote IP ?
by afoken (Parson) on May 09, 2009 at 15:38 UTC

    Note that you can not and will never see google or perlmonks in the ARP listings. All internet traffic goes through galileo7 (192.168.1.1). So, on a MAC level, all my machines just have to know that they have to ask galileo7 to deliver packets to the rest of the world.

    Alexander

    --
    Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

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