Re: Routing Problem

From: Thomas Foster (tbonius_at_comcast.net)
Date: 02/02/05

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    To: "Gustafson, Tim" <tjg@meitech.com>
Date: Wed, 2 Feb 2005 06:26:01 -0800

    Sounds like the man page for routed might be what you seek

    http://www.freebsd.org/cgi/man.cgi?query=routed&sektion=8

    T

    ----- Original Message -----
    From: "Gustafson, Tim" <tjg@meitech.com>
    To: "Thomas Foster" <tbonius@comcast.net>
    Cc: <questions@freebsd.org>
    Sent: Wednesday, February 02, 2005 5:02 AM
    Subject: RE: Routing Problem

    > Thomas (and John too),
    >
    > Let me clarify a little bit.
    >
    > What I have is this:
    >
    > A single FreeBSD web server with a single NIC in it
    > Two T1 routers, each with a different subnet.
    >
    > My FreeBSD box has two IP addresses assigned to it, one from the first
    > subnet and one from the second subnet.
    >
    > I want to use round-robin DNS to direct half my web traffic to the first
    > IP and half to the second IP.
    >
    > As I said to John in a private e-mail earlier this morning, I have a
    > Windows 2000 box that is doing exactly this with these two subnets right
    > now. I know it "can" be done. I have a feeling that the FreeBSD TCP
    > stack lacks the capability. By the way, this also works with Cisco
    > hardware. I have used Cisco equipment in this same configuration in the
    > past.
    >
    > I think they way it SHOULD work is that you should be able to give a
    > FreeBSD box multiple default gateways. When FreeBSD gets a packet to an
    > IP on the first subnet, it should use the default gateway that is also
    > on that subnet. When FreeBSD gets a packet to an IP on the second
    > subnet, it should use the second default gateway. This seems to be the
    > logic that Windows (and Cisco) uses.
    >
    > Tim Gustafson
    > MEI Technology Consulting, Inc
    > tjg@meitech.com
    > (516) 379-0001 Office
    > (516) 480-1870 Mobile/Emergencies
    > (516) 908-4185 Fax
    > http://www.meitech.com/
    >
    >
    >
    > -----Original Message-----
    > From: Thomas Foster [mailto:tbonius@comcast.net]
    > Sent: Wednesday, February 02, 2005 7:57 AM
    > To: Gustafson, Tim
    > Cc: questions@freebsd.org
    > Subject: Re: Routing Problem
    >
    >
    > Hi Tim..
    >
    > If you have multiple interfaces and you configure a default gateway for
    > each
    > interface, the default metric determination that is based on the speed
    > of
    > the interface usually uses the fastest interface for default gateway
    > traffic. This is usually desirable in configurations in which the
    > computer
    > is connected to the same network.
    >
    > This behavior can become a problem when the computer exists on two or
    > more
    > disjointed networks (networks that do not provide symmetric reachability
    > on
    > layer3). Symmetric reachability exists when packets can be sent to and
    > received from an arbitrary destination.
    >
    > Because the TCP/IP version4 protocol uses a single default route in
    > FreeBSD's routing table at any one time for default route traffic,
    > default
    > routers configured on multiple interfaces connected to two or more
    > disjointed networks can wreak routing traffic havoc.
    >
    > In FreeBSD, you can manually configure the routing table for the
    > individual
    > interfaces.. but it sounds to me as if you are attempting to use two
    > ethernet interfaces connected to two disjointed networks connected to
    > routers with two seperate subnets in order to balance http requests to
    > one
    > server.. is this the case? I guess I am not fully understanding your
    > configuration ...
    >
    > T.
    >
    >
    > ----- Original Message -----
    > From: "Gustafson, Tim" <tjg@meitech.com>
    > To: "Thomas Foster" <tbonius@comcast.net>
    > Cc: <questions@freebsd.org>
    > Sent: Wednesday, February 02, 2005 4:06 AM
    > Subject: RE: Routing Problem
    >
    >
    >> Thomas,
    >>
    >> No, I'm not using this box as a router. It is a web server, and I
    > need
    >> to spread the load of my web traffic across two separate T1s.
    >>
    >> I can't just add routes. You need a default route, or parts of the
    >> internet would become inaccessible. In my case, you need TWO default
    >> routes. I have set up Cisco equipment and Windows workstations with
    > two
    >> default routes in the past, and it has worked. In fact, I have one
    >> Windows box right now that is configured on both these networks with
    > two
    >> default gateways, and it is working.
    >>
    >> There has to be a way to make it work on FreeBSD.
    >>
    >> Tim Gustafson
    >> MEI Technology Consulting, Inc
    >> tjg@meitech.com
    >> (516) 379-0001 Office
    >> (516) 480-1870 Mobile/Emergencies
    >> (516) 908-4185 Fax
    >> http://www.meitech.com/
    >>
    >>
    >>
    >> -----Original Message-----
    >> From: Thomas Foster [mailto:tbonius@comcast.net]
    >> Sent: Wednesday, February 02, 2005 4:48 AM
    >> To: Gustafson, Tim
    >> Cc: questions@freebsd.org
    >> Subject: Re: Routing Problem
    >>
    >>
    >> Im confused.. if you have two T1s, then are using /30s dor the ranges?
    >> If
    >> so.. what about not giving a default gateway for either one and just
    > add
    >>
    >> routes...
    >>
    >> Are you attempting utilize this as just a router.?
    >>
    >> Theres a section that covers setting up routing on interfaces in the
    >> handbook:
    >>
    >>
    > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-routin
    >> g.html
    >>
    >> Hope this helps
    >>
    >> T
    >> ----- Original Message -----
    >> From: "Gustafson, Tim" <tjg@meitech.com>
    >> To: <freebsd-questions@freebsd.org>
    >> Sent: Tuesday, February 01, 2005 5:35 PM
    >> Subject: Routing Problem
    >>
    >>
    >>>I am having a problem setting up a multi-homed host. I have two
    >>> separate T1 internet connections, and one physical NIC in my FreeBSD
    >>> box. The two networks are as follows:
    >>>
    >>> Connection 1:
    >>> LAN Address: 1.2.3.24/25
    >>> Router Address: 1.2.3.1
    >>>
    >>> Connection 2:
    >>> LAN Address: 4.5.6.106/29
    >>> Router Address: 4.5.6.105
    >>>
    >>> I would like to set up my FreeBSD box so that I can connect to either
    >>> LAN address from the outside world. The problem is that I cannot
    >>> specify two default gateways. Right now, I have 1.2.3.1 set up as a
    >>> default gateway, and I can get to the 1.2.3.24 IP from the outside
    >>> world. However, I can't get to 4.5.6.106. I can't even ping it.
    >> From
    >>> the FreeBSD box, I can ping 4.5.6.105, and from the outside world I
    >> can
    >>> ping 4.5.6.105, but I can't ping 4.5.6.106 from the outside world.
    >>>
    >>> Is there any way to make this work? How can I make FreeBSD have two
    >>> default gateways? I read somewhere about being able to set up source
    >>> routing, but I haven't been able to find any HOWTO's about that.
    >>>
    >>> Any help is greatly appreciated.
    >>>
    >>
    >>
    >>
    >
    >
    >

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