RE: anyone who saw this arp traffic?

From: Badger, Jared (Jared.Badger_at_acs-inc.com)
Date: 03/03/05

  • Next message: Hamish Stanaway: "Re: securing linux webserver?"
    To: Amit Ronen <amitro@spiderservices.com>
    Date: Wed, 2 Mar 2005 17:33:02 -0700 
    
    

    Amit,

    This is called a "gratuitous ARP". Stations will often do this to check if
    an address is in use before accepting a DHCP lease. Use your protocol
    analyzer to see if this ARP behavior coincides with DHCP. Not sure why
    you're seeing it on multiple links or why stuff from 172.16.x.x is showing
    up on a network where it doesn't belong...

    -Jared Badger

    PS. Here is the info for that MAC address.

    00-10-DC (hex) MICRO-STAR INTERNATIONAL CO., LTD.
    0010DC (base 16) MICRO-STAR INTERNATIONAL CO., LTD.
                                    NO. 69, LI-DE ST., JUNG-HE CITY
                                     TAIPEI HSIEN
                                    TAIWAN, REPUBLIC OF CHINA

    00-0C-76 (hex) MICRO-STAR INTERNATIONAL CO., LTD.
    000C76 (base 16) MICRO-STAR INTERNATIONAL CO., LTD.
                                    No 69, Li-De Street, Jung-He City, Taipe
                                    Taipei
                                    TAIWAN, REPUBLIC OF CHINA

    -----Original Message-----
    From: Amit Ronen [mailto:amitro@spiderservices.com]
    Sent: Wednesday, March 02, 2005 1:43 AM
    To: security-basics@securityfocus.com
    Subject: RE: anyone who saw this arp traffic?

    Try checking if there is a VPN device that use Virtual IP's for external VPN
    users - similar to Checkpoint office mode....

    -----Original Message-----
    From: Andrew Shore [mailto:andrew.shore@holistecs.com]
    Sent: ב 28 פברואר 2005 18:09
    To: dissolved; Monty Ree
    Cc: security-basics@securityfocus.com
    Subject: RE: anyone who saw this arp traffic?

    I've seen similar situations when using Virtual server technologies;

    Often "internal" logical networks will throw martens onto the physical
    network.

    HTH Andy

    -----Original Message-----
    From: dissolved [mailto:dissolved@comcast.net]
    Sent: 25 February 2005 00:40
    To: 'Monty Ree'
    Cc: security-basics@securityfocus.com
    Subject: RE: anyone who saw this arp traffic?

    Are any secondary interfaces or sub-interfaces defined on a gateway?
    -----Original Message-----
    From: Monty Ree [mailto:chulmin2@hotmail.com]
    Sent: Tuesday, February 22, 2005 8:41 PM
    To: security-basics@securityfocus.com
    Subject: anyone who saw this arp traffic?

    Hello, all.

    When I capture network traffic at server farm,I can see lots of arp
    broadcast like below.
    But there is no server which use 172.16.x.x ip address.
    and curiously,

    1. source ip and destination ip is same
    2. more curiously, same traffic(source mac:0:10:dc:f1:f7:64 , source
    ip:172.16.97.157) is seen at my office.
    3. I can also see this traffic(source mac:0:10:dc:f1:f7:64 , source
    ip:172.16.97.157 ) at other IDC.

    Have you ever seen this traffic?
     
    Thanks in advance.

    10:15:26.759069 0:10:dc:f1:f7:64 Broadcast arp 60: arp who-has
    172.16.97.157 (Broadcast) tell 172.16.97.157
    10:15:26.803792 0:c:76:4e:4:c8 Broadcast arp 60: arp who-has 172.16.100.103
    (Broadcast) tell 172.16.100.103
    10:15:26.955878 0:c:76:4e:4:c8 Broadcast arp 60: arp who-has 172.16.100.103
    (Broadcast) tell 172.16.100.103
    10:15:26.967737 0:10:dc:f1:f7:64 Broadcast arp 60: arp who-has
    172.16.97.157 (Broadcast) tell 172.16.97.157

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  • Next message: Hamish Stanaway: "Re: securing linux webserver?"

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