Default Gateways and Router Connections

Archived from groups: microsoft.public.windowsnt.protocol.tcpip (More info?)

I have three sites using Windows NT 4.0 servers and VPN
connections via T1 lines for connectivity. Site A is the
main facility with sites B and C connecting to Site A's
router for MS Exchange and MS SQL servers. Site A has
two routers, router1 allows connectivity to Sites B and C
and router2 allow Internet access. If the default
gateway on the Exchange Server is set to router1 then
both Sites B and C can connect to it without any
problems. If the Exchange Server's default gateway is
set to router2 for Internet access, Site B can still
connect to the Exchange Server but Site C cannot
connect. This scenario is the same for all the other
servers on Site A. Also, Site A can ping both Site B and
C's router no matter if its default gateway is set to
router1 or router2. I need the default gateway of the
Exchange Server to point to router2 so it can send Email
via the Internet. Why can Site C only connect to Site A
file servers if the Site A file servers default gateway
is pointing to router1?
3 answers Last reply
More about default gateways router connections
  1. Archived from groups: microsoft.public.windowsnt.protocol.tcpip (More info?)

    In article <4a0b01c4c759$94fc5c80$a401280a@phx.gbl>,
    Bill Freeze <narron3211@yahoo.com> wrote:
    > ... Site A has
    >two routers, router1 allows connectivity to Sites B and C
    >and router2 allow Internet access. If the default
    >gateway on the Exchange Server is set to router1 then
    >both Sites B and C can connect to it without any
    >problems. If the Exchange Server's default gateway is
    >set to router2 for Internet access, Site B can still
    >connect to the Exchange Server but Site C cannot
    >connect. ...
    > ... Why can Site C only connect to Site A
    >file servers if the Site A file servers default gateway
    >is pointing to router1?

    What subnets are A, B, and C in?

    What does the Exchange Servers routing table look like?

    --
    -- Rod --
    rodd(at)polylogics(dot)com
  2. Archived from groups: microsoft.public.windowsnt.protocol.tcpip (More info?)

    A, B, and C are in private networks of 172.16.30.0,
    172.16.20.0, and 172.16.40.0 respectively. They are use
    subnet mask of 255.255.255.0

    The following is a copy and paste of the Exchange
    Servers's routing table:

    C:\>route print

    Active Routes:

    Network Address Netmask Gateway
    Address Interface Metric
    0.0.0.0 0.0.0.0 172.16.30.11
    172.16.30.105 1
    0.0.0.0 0.0.0.0 172.16.30.35
    172.16.30.105 1
    127.0.0.0 255.0.0.0
    127.0.0.1 127.0.0.1 1
    172.16.20.0 255.255.255.0 172.16.30.11
    172.16.30.105 1
    172.16.20.155 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.20.156 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.20.165 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.20.167 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.20.169 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.20.171 255.255.255.255 172.16.30.11
    172.16.30.105 1
    172.16.30.0 255.255.255.0 172.16.30.105
    172.16.30.105 1
    172.16.30.105 255.255.255.255
    127.0.0.1 127.0.0.1 1
    172.16.40.0 255.255.255.0 172.16.30.11
    172.16.30.105 1
    172.16.255.255 255.255.255.255 172.16.30.105
    172.16.30.105 1
    224.0.0.0 224.0.0.0 172.16.30.105
    172.16.30.105 1
    255.255.255.255 255.255.255.255 172.16.30.105
    172.16.30.105 1

    The only question I have with the routing table is the
    172.16.20.155-172.16.20.171 IP Addresses. These are not
    static IP address on the 172.16.20.0 network or on the
    Exchange Server. I have used the "Route Delete" command
    to remove these addresses but they keep reappearing.
  3. Archived from groups: microsoft.public.windowsnt.protocol.tcpip (More info?)

    In article <6efa01c4ccd7$26bbbfd0$a601280a@phx.gbl>,
    Bill Freeze <anonymous@discussions.microsoft.com> wrote:
    >A, B, and C are in private networks of 172.16.30.0,
    >172.16.20.0, and 172.16.40.0 respectively. They are use
    >subnet mask of 255.255.255.0
    > ...
    > Network Address Netmask Gateway Address Interface
    > 0.0.0.0 0.0.0.0 172.16.30.11 172.16.30.105
    > 0.0.0.0 0.0.0.0 172.16.30.35 172.16.30.105

    Your problem is you've got two default gateways.

    From the rest of your routing table it looks like 'router1' is
    172.16.30.11 connecting to sites B & C and 'router2' is 172.16.30.35
    connecting to the internet.

    You've got the needed /24 routes
    > 172.16.20.0 255.255.255.0 172.16.30.11 172.16.30.105
    > 172.16.30.0 255.255.255.0 172.16.30.105 172.16.30.105
    > 172.16.40.0 255.255.255.0 172.16.30.11 172.16.30.105
    for your three networks.

    Try to delete the default route to 'router1'
    > 0.0.0.0 0.0.0.0 172.16.30.11 172.16.30.105
    the only addresses routed via that path should be 172.16.20/24 and
    172.16.40/24

    --
    -- Rod --
    rodd(at)polylogics(dot)com
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