Difference between ARP Cache and DNS cache?

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    Difference between ARP Cache and DNS cache?

    Hello - could someone guide me the differenc between ARP and DNS cache? I know ARP cache is for 10 minutes while DNS is for some days - but why?

    Any guidance is apprecited.

    Thanks

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    ARP - Address Resolution Protocol.
    DNS - Domain Name System.

    ARP translates an IP adrress (e.g 192.168.0.1) to a MAC address (e.g. 00:11:12:13:14:15)
    DNS translates a name (e.g. Example Web Page) to an IP address (e.g. 212.178.0.19)

    --
    Mats
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    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by namasteall2000 View Post
    Hello - could someone guide me the differenc between ARP and DNS cache? I know ARP cache is for 10 minutes while DNS is for some days - but why?

    Any guidance is apprecited.

    Thanks
    First, although ARP and DNS both map higher-level names to lower-level names, they are really quite different.

    The DNS cache time is actually configurable by the domain owner. The reason the cache time is (usually) very long is because the Internet is much slower than a local network (at least traditionally). Domain->address mappings don't change very often, so a lower cache time would simply increase the number of DNS lookup requests on the Internet at large, with no real benefit. Note that this caching is hierarchical.

    On the other hand, a LAN is (supposedly) fast, and the devices connected to the LAN may change frequently. In that case, it isn't harmful to have a much lower cache residence time.

    In both cases, we suffer from "cache poisoning" attacks where an evil party can inject a false cache entry that can cause packets to be sent to the wrong destination. In that respect a lower cache residence time is better, because the poisoned entry will be purged sooner.
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

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    Thanks a bunch.

    [Brewbuck - you ansered what I was looking for - a very basic difference.

    Once again thanks for the help.

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    Quote Originally Posted by namasteall2000 View Post
    Hello - could someone guide me the differenc between ARP and DNS cache? I know ARP cache is for 10 minutes while DNS is for some days - but why?

    Any guidance is apprecited.

    Thanks
    i need an answer urgently

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by gabeve
    i need an answer urgently
    You urgently need to read this whole thread.
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    Quote Originally Posted by gabeve View Post
    i need an answer urgently
    42 - that's a very useful answer

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    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

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    hostnames

    is it neccesary to have hostnames? Justfy your answer?

    please i need an answer. HELP

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    hello please reply

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    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by gabeve View Post
    hello please reply
    No thanks. I checked the list of the most important people in the world and you weren't on it.
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

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