RE: Two ethernet cards, one IP?!?
Thanks, especially for the bit about the two cards working as expected
when connected to two separate switches.
I was trying to test the server before taking it up to our ISP, and I set
up both NIC's on one switch, thinking to test them by disconnecting one
cable at a time. This returned the strange behaviour I reported: when
one cable was disconnected, neither interface answered; when that was
re-connected and the other disconnected, both answered!
Now trying with each NIC on a different switch gives what I would expect:
connection from each net is severed when the cable is disconnected, and
re-established when the cable is reconnected.
Quite how such strange behaviour can arise when both cards are
connected to one switch is well beyond me.
A quick check with a Realtek card in place of the EtherExpress PCI
revealed the same behaviour, as did a quick re-compile of the kernel with
the ethernet card module as a separate driver. Really strange... The
strangeness only disappeared when I put the cards on two separate
switches.
Thanks and best regards,
George Karaolides 8, Costakis Pantelides St.,
tel: +35 79 68 08 86 Strovolos,
email: george@karaolides.com Nicosia CY 2057,
web: www.karaolides.com Republic of Cyprus
On Tue, 25 Sep 2001, Theo Zourzouvillys wrote:
> Date: Tue, 25 Sep 2001 21:07:14 +0100
> From: Theo Zourzouvillys <theo@crazygreek.co.uk>
> To: 'George Karaolides' <george@karaolides.com>
> Cc: debian-user@lists.debian.org
> Subject: RE: Two ethernet cards, one IP?!?
>
>
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>
> > Hi,
> >
> > Thanks for the reply.
> >
> > I shall certainly try using ipchains for this, and will let you
> > know if it works.
> >
> > Best regards,
> >
> > George Karaolides 8, Costakis Pantelides St.,
> > tel: +35 79 68 08 86 Strovolos,
> > email: george@karaolides.com Nicosia CY 2057,
> > web: www.karaolides.com Republic of Cyprus
> >
> >
>
> Another thing worth noting is any virtual interfaces created on eth1
> will not work for some strange reason.
>
> However, I looked on one of our firewall boxes, which is separating
> two networks, routing, and filtering packets. It has one IP address
> on either network. This is working fine:
>
> ~~~~~~~~~~~~~~
>
> [root@w00t apache]# uname -a
> Linux w00t 2.4.9 #2 Thu Sep 20 02:36:56 BST 2001 i686 unknown
>
> [root@w00t apache]# route -n
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref
> Use Iface
> 10.0.0.1 0.0.0.0 255.255.255.255 UH 0 0
> 0 eth1
> 194.93.14x.xxx 0.0.0.0 255.255.255.128 U 0 0
> 0 eth1
> 194.93.12x.xxx 0.0.0.0 255.255.255.0 U 0 0
> 0 eth0
> 192.168.0.0 194.93.14x.x 255.255.255.0 UG 0 0
> 0 eth1
> 0.0.0.0 194.93.12x.x 0.0.0.0 UG 0 0
> 0 eth0
>
> [root@w00t apache]# ifconfig
> eth0 Link encap:Ethernet HWaddr 00:02:B3:35:DC:22
> inet addr:194.93.12x.xxx Bcast:194.93.12x.255
> Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:368304 errors:0 dropped:0 overruns:0 frame:0
> TX packets:28724 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> Interrupt:5
>
> eth1 Link encap:Ethernet HWaddr 00:02:B3:35:DC:23
> inet addr:194.93.14x.xxx Bcast:194.93.14x.255
> mask:255.255.255.128
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:67172 errors:0 dropped:0 overruns:0 frame:0
> TX packets:58424 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> Interrupt:5 Base address:0x2000
>
> *snip loopback*
>
> ~~~~~~~~~~~~~~
>
> The eepro100 module is compiled into the kernel.
>
> Thinking back, last year I set up some ISP2150's (virtually the same,
> but 2U high) that had one onboard NIC and we added one PCI eepro100
> into them. They worked fine, as we had one on a 213.206.4.xx address
> and one on a 10.0.0.x address; on totally different switches.
>
>
> Theo Zourzouvillys
> Global Network Consultant
>
> + Notnet Consultancy [ www.notnet.co.uk ]
> - Specialising in Unix security, ISP Start-up and regeneration,
> - MySQL solutions, E-commerce, and Load balancing.
> + Notnet.co.uk - Quality web hosting at an affordable price
> - http://www.notnet.co.uk/
> + Mobile: +44 7747 844 300
> + theo@crazygreek.co.uk
>
>
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