Taking this a step further I'm trying to do something similar and
getting _strange_ results. Using totally fake IPs here is what I'm
trying to set up. ( As typing this I see Chuck just posted to the
thread with similar information. )
Host system with three NICs: eth0, eth1, eth2. Fedora Core 5 and all
guests are FC5 using Daniel's excellent RPMs and was just updated this AM.
eth0 is connected to a switch/router for one up-stream provider and has
a block of 16 addresses designated for it: 123.45.67.192/28.
eth1 is connected to different switch/router for a different upstream
provider with a block of 16 addresses designated for it: 98.76.54.192/28.
eth2 is connected to a switch which is the private in-house network for
connection to the backup server, fileserver, and other non-public
resources and can use any address in the 192.168.254.0/24 network. IT
currently isn't configured or activated. I'll cross that bridge later.
I've configured four guests so far. Three use the eth0 connection and
one uses the eth1.
I have created two files in /etc/sysconfig/network-scripts:
route-eth0
route-eth1
They are using what I think is the current ( Redhat approved ) format.
GATEWAY0=123.45.67.1
NETMASK0=255.255.255.240
ADDRESS0=123.45.67.192
and
GATEWAY1=98.76.54.1
NETMASK1=255.255.255.240
ADDRESS1=98.76.54.192
I have assigned the IPs 123.45.67.193 and 98.76.54.193 to the two NICs
for the host to use. ( Enforcement of the classless subnet isn't being
enforced as the company the server is at has the full C Class for both
IP ranges -- they're an ISP. )
ifcfg-eth0 contains:
DEVICE=eth0
BOOTPROTO=static
BROADCAST=66.193.36.255
HWADDR=00:00:00:00:00:00 # faked up
IPADDR=123.45.67.193
NETMASK=255.255.255.0
NETWORK=123.45.67.0
ONBOOT=yes
and ifcfg-eth1 contains:
DEVICE=eth1
BOOTPROTO=static
HWADDR=01:01:01:01:01:01 # faked up
BROADCAST=98.76.54.255
IPADDR=98.76.54.193
NETMASK=255.255.255.240
NETWORK=98.76.54.192
ONBOOT=yes
Lastly iptables is pretty open.
The problem is that though I can ping from a different network to both
of the host's to IPs and I can ping out from the three guests that use
eth0 and I can ping the eth1 guest from a eth0 guest I can't ping from
the eth1 guest to the outside world. The cursor just sits there
blinking at me. #$%^&* computers. :-)
All the guests were created using the same set of commands with only the
contexts, IPs, interface etc. different.
So I'm hoping it is just something really stupid or overlooked on my part.
Hope this is hijacking hte thread too much.
Rod
--
Herbert Poetzl wrote:
On Thu, Sep 28, 2006 at 07:35:09PM -0400, Chuck wrote:
my 32 net guests cannot contact outside 39 net machines on our same
network. they can contact other 39 net guests on the same host.
conversely, the external 39 net machine cannot contact any 32 net ip
on the vserver host or any guest..
I assume you mean something like 10.32.0.x/24 and 10.39.0.y/24
here (well, at least it sounds like that is what you mean)
the problem i had was when within a 32net guest if i ping a 39 net
external host, it goes out our 39 net card to the external host gets
answered and routed back into our host on 32net since the source ip
header in the packet is 32 net and the system ignores it.
yes, by default, the host is allowed to choose any network
address which is assigned to an interface, the reverse path
filter basically blocks packets which could not have originated
from that interface, because it does not hold that ip
setting below to 0 cures that.
so, what you basically did, is to allow the packets to leave
the interfaces with an ip from a different interface/routing
too (which is harmless, but probably not what you actually
wanted)
am i doing something extremely stupid by disabling this or is it
secure enough not to worry?
we are protected by tons of acls in various routers plus a very
strict iptables on the host.
the better approach would be to set up two routing tables,
(given that there are two nics/routes on the host), and
use source based routing to figure the proper interface
but if that 'works for you' then it is no big deal, as I
said, it's usually off by default ...
HTH,
Herbert
i found below in sysctl.conf was set to 1. if i set it to 0 as shown
everything works properly..
# Enables source route verification. 0 disables
net.ipv4.conf.default.rp_filter = 0
--
Chuck
"...and the hordes of M$*ft users descended upon me in their anger,
and asked 'Why do you not get the viruses or the BlueScreensOfDeath
or insecure system troubles and slowness or pay through the nose
for an OS as *we* do?!!', and I answered...'I use Linux'. "
The Book of John, chapter 1, page 1, and end of book
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