Cashing Arp
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Thread: Cashing Arp

  1. #1

    Question Cashing Arp

    i wana build a static arp table for my network dont know why but im going to do it
    ok i know that if you open up MSDos promt and type arp -s 192.168.0.1 00-02-h2-3c-26-00 that it wil make a static entire into your arp table but when the computer is rest so is the arp table and i want to know how you can cash and or store you static routs so you dont have to keep doing um?


    P.S.
    if you got any good tutorial on arp or ettercap or nmap post um
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  2. #2
    Priapistic Monk KorpDeath's Avatar
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    Adding arp entries and adding static routes differ. If you want to add a static routes just type out the 'route add' command and add a -p to the end. (in windows)


    P.S. It's caching, not cashing. From the rrot word 'cache'. Not to be picky or anything.
    Mankind have a great aversion to intellectual labor; but even supposing knowledge to be easily attainable, more people would be content to be ignorant than would take even a little trouble to acquire it.
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  3. #3
    AO's MMA Fanatic! Computernerd22's Avatar
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    After you do that command your gonna wanna use arp -a this does

    Displays current ARP entries by interrogating the current
    protocol data. If inet_addr is specified, the IP and Physical
    addresses for only the specified computer are displayed. If
    more than one network interface uses ARP, entries for each ARP
    table are displayed.

  4. #4
    AO Ancient: Team Leader
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    Corp:

    Not to be picky or anything but it's root, not rrot.......<ROFLMAO>

    P.S. It's caching, not cashing. From the rrot word 'cache'. Not to be picky or anything.
    Sorry mate... I couldn't resist it.... Gotta read what you type when you correct spelling.....
    Don\'t SYN us.... We\'ll SYN you.....
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  5. #5
    Senior Member
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    pr0letariat,

    Here is general syntax in simplest form: if you want to see all options available type "route add /?" at DOS prompt.


    route ADD -p {destination network} MASK (destination mask} {gateway}

    (the -p option makes route permanent and does not clear after reboot)



    here is syntax with an example: to reach destination net 157.0.0.0 with mask 255.0.0.0, forward packet to 157.55.80.1

    route ADD -p 157.0.0.0 MASK 255.0.0.0 157.55.80.1

    Im curious, are you adding static routes for educational purposes to better understand routing/etc..or do you feel you need to in order to access outside networks/subnets...
    because if you have a default gateway configured (and there is only one gateway/router on your LAN), then you do not need to configure static routes.

    Good Luck
    Cheers...

  6. #6
    AO Ancient: Team Leader
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    Thinking about this caching the ARP table could be counter-productive.... Not to mention that setting routes and making the ARP table effectively permanent are completely different.

    The following come to mind when you make the arp table permanent:

    1. DHCP environment. Locking an ARP address to an IP will come back to bite you.
    2. In a large environment you will increase network traffic and slow your own response because the ARP table is set to flush at a given size to eliminate old entries. Thus setting a lot of entries decreases the time between arp flushes and increases ARP requests.
    3. NIC failure in a fixed environment will cause communication failure when it is replaced.

    Setting route has nothing to do with the ARP table. When you set a route and you request something from that IP address your computer still sends out an ARP request if the subnet is local unless you have the ARP in the cache or you have fixed the arp address to the IP in the ARP table.... thus, see above.

    Fixing both will cause you horrendous troubleshooting problems when something fails.

    Now.... Could fixing a ARP table create a security issue.... Er, yep.... If I'm on your subnet and own a given machine and fix your ARP table.... I can send all your network requests to me first regardless of the proper IP. Then, the program that receives them can log them and forward them to the proper address, receive the replies and forward them back to you..... Hmmmmm, I just sniffed everything you do on the network.... No promiscuous mode required and very hard to detect.

    Now... Having woffled my way through that why do I feel that the question may be directed towards fixing an ARP table so that some entries are permanently permanent.... therefore the question has a dark side......

    There goes that suspicious, crusty old bastard in me again.....
    Don\'t SYN us.... We\'ll SYN you.....
    \"A nation that draws too broad a difference between its scholars and its warriors will have its thinking done by cowards, and its fighting done by fools.\" - Thucydides

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