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Internet router + ADSL modem

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  • Internet router + ADSL modem

    Hi to everyone!

    I am novice in Cisco routers, so I rely on yours tips and recommendations


    ADSL modem, ISP keeps under control this modem, I haven't access to it.
    The only things I know about this modem are:
    - it is in briding mode
    x.y.z.234 - modem IP
    x.y.z.233 - default Ip (located physically on ISP side)
    - modem is transparent .... (as per ISP words...)

    LinkSys internet router RV082, with nice GUI
    I can log into this router and configure it as I want
    Our company has statip ip range from
    x.y.z.112 to x.y.z.117 with subnet mask
    Note that everywhere x.y.z. means the same IP

    I set router in NAT mode,
    LAN IP:
    WAN IP: x.y.z.114
    Default gateway: x.y.z.113

    Because we use exchange mailserver, I set
    one-to-one NAT NIC) - x.y.z.115(MX record on ISP site)

    No connection to the internet..........
    ISP suggested me to create some routing table on the router...How ?????
    And what's the subnet mask for x.y.z.234 ? or ?

    Should I set router in Gateway or Router mode ?

    Any ideas ?
    Maybe, somebody can give me links to websites with explnation how to configure this equipment for this case ?

    Thank you in advance

    Mihail Kravsun

  • #2
    Re: Internet router + ADSL modem

    If the ADSL modem is in bridging mode- ignore it and its addresses.

    First set the WAN IP Address of the router to the address. The gateway address of this subnet should have been provided by your ISP but normally is is the prior address or with your ISP.

    By trying to set the GW to the .113 address all you are doing is telling the ISP/Internet that to send all of the packets coming from your router back to your router because you own these addresses.

    The ISP your subnet mask for 5 usable addresses should be
    Even though this gives you 6 addresses the ISP takes 1 for thier gateway.

    This should get you online.

    Once online set the Linksys to foward the .115 address to your internal mail address Of course you should have your DNS/MX records set to forward email to the public IP.

    Don't try to mess with static routes, you don't need them

    I hope this helps

    Good Luck