[Voyage-linux] Static IP on Alix

[Roberto Arena]

Thanks,

Ok the subnet of eth0-eth1-eth2 now are in different subnet and i have
solved the problem.

2011/9/4 Gustin Johnson <gustin at meganerd.ca>

> In addition to what Adrian said, you also do not need to define the
> DNS and gateway IPs twice.  If one of the interfaces is getting it's
> IP from DHCP, then those variables are also going to come from the
> DHCP server.
>
> Is there a reason that you are even using DHCP here?  Do you need more
> than one IP on the same subnet?
>
> If you want to reach the box via either interface, then a bridge with
> a single IP is probably what you want.
>
> On Sun, Sep 4, 2011 at 3:07 PM, Adrian Reyer <voyage-linux at lihas.de>
> wrote:
> > Hi Roberto,
> >
> > On Sat, Sep 03, 2011 at 12:00:47PM +0200, Roberto Arena wrote:
> >> * auto eth0
> >> iface eth0 inet static
> >>        address 192.168.1.127
> >>        netmask 255.255.255.0
> >>        broadcast 192.168.1.255
> >>        gateway 192.168.1.249
> >>        dns-nameservers 212.216.112.112*
> >> * auto eth1
> >> iface eth1 inet static
> >>        address 192.168.1.128
> >>        netmask 255.255.255.0
> >>        broadcast 192.168.1.255
> >>        gateway 192.168.1.249
> >>        dns-nameservers 212.216.112.112*
> >
> > What does the '*' mean? If they actually are in the file it is wrong.
> > If the resolvconf package is installed it should work. At least it does
> > so here.
> > However, having 2 interfaces within the same IP range asks for trouble.
> > Why do you want to have eth0 and eth1 within the same network?
> > - playing switch
> >  -> use a bridge instead
> > - adding a second IP
> >  -> use eth0:0 for a virtual IP instead
> > - redundant links to the same network
> >  -> use a bridge on the 2 devices
> > - boosting performance
> >  -> use a bond-device on the 2 devices if your switch supports bonds
> > You can combine the above.
> >
> > If you stick with your configuration and both network interfaces link to
> > the same physical network, e.g. no proxy arp involved, be aware, the
> > linux kernel always uses the interface for outgoing packets that comes
> > first in the routing table, no matter which interfaces IP address you
> > connect to.
> > You can get round this by using source routing with alternate routing
> > tables. That way you can make sure IP a traffic leaves the box via
> > interface a and IP b traffic leaves the box via interface b.
> >
> > Another problem might be IP spoof protection. If you have traffic coming
> > in via an interface that has no route to that IP it will be dropped.
> > You can fix this by disabling spoof protection for that interface with
> > echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter
> > or permanently by adding this to /etc/sysctl.conf.
> >
> > The kernel answers a packet via the first interface that sees the
> > packet, no matter if the IP is right. If I recall correctly, this can be
> > changed with
> > echo 0 > /proc/ss/net/ipv4/conf/eth0/shared_media
> > or, again, by adding this to /etc/sysctl.conf
> > Obviously you need to state these lines for every interface in question.
> >
> > Another point might be your switch. It might block your ports if it
> > detects packets with same MAC address on 2 interfaces the same time,
> > again as it might think your did a short circuit. Check if you can
> > configure your switch to suit your needs or if you need a bridged device
> > with STP enabled.
> >
> > Regards,
> >        Adrian
> > --
> > LiHAS - Adrian Reyer - Hessenwiesenstraße 10 - D-70565 Stuttgart
> > Fon: +49 (7 11) 78 28 50 90 - Fax:  +49 (7 11) 78 28 50 91
> > Mail: lihas at lihas.de - Web: http://lihas.de
> > Linux, Netzwerke, Consulting & Support - USt-ID: DE 227 816 626 Stuttgart
> >
> > _______________________________________________
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> > Voyage-linux at list.voyage.hk
> > http://list.voyage.hk/mailman/listinfo/voyage-linux
> >
>



-- 
*Roberto Arena
**technical Manager*
*r.arena at gisat.net
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*
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