ArcosCom Linux User wrote:
Thanks for the response, I explain a bit more.
The 3 uplinks have 3 public IP addressess (one per uplink), and are "ADSL"
links, one public ip per interface.
eth1 and eth2 have, each one, their direct connect to their ADSL gateway.
eth3 (public IP) and eth0 (private IP) share the same ethernet network.
Physically, this shared ethernet have many wireless bridges (using STP) to
link all the buildings we need to link.
The test I done to see the latences are send 2 pings to the same physical
place to diferent defices from the linux box.
One ping from router to adsl gateway (eth3->uplink3 gateway) and, at the
same time, one ping from router to a workstation (eth0->LAN).
Physically the two pings go trought the same physicall path and end in the
same switch where the uplink3 gateway and the test workstation are.
In router:
a) I MASQUERADE the IP by interface (-j MASQUERADE), because I need to
have all ougoing frames control.
b) I balance the routers (as described in lartc and use magle to allow
the responses from the incomming interface where they arrives.
c) I use tc (using HTB qdiscs) for the QoS (the problem became with QoS
disabled too, don't think this were the problem).
Yesterday, I found a local kernel text file called
/usr/share/doc/kernel-doc-2.6.18/Documentation/networking/ip-sysctl.txt
(internet is not all) where I see a very usefull information about ip
parameters and appears that tweaking some of them will solve some problems
with ARP, but really I don't know many of these parameters and only
appears to be usefull for me some of them: arp_filter, arp_accept,
arp_ignore, rp_filter.
My distro is CentOS 5.2 whith the last kernel (2.6.18 based).
Expect that with this information the problem could be more explained than
in the initial e-mail.
Regards
El Mar, 9 de Septiembre de 2008, 23:49, Grant Taylor escribió:
On 09/09/08 03:29, ArcosCom Linux User wrote:
Physically there are 3 ethernet networks, one for the uplink 1, other
for uplink 2, and the third is for the lans and the uplink 3. I
forced to share the ethernet for the LANs and uplink 3.
Ok...
The router has 4 interfaces, eth1 for uplink 1, eth2 for uplink 2,
eth3 for uplink 3 and eth0 for the LANs.
Just so I understand you correctly. You have four physical ethernet
interfaces in the system, but eth3 and eth0 are connected to the same
ethernet network (broadcast domain)?
(Presuming that the above understanding is correct.) Why do you have
eth0 (LANs) and eth3 (uplink 3) connected to the same ethernet network?
Rather why not have them be different networks from each other?
The problem I have is that, without a constant time or reason,
sometimes I detect latences between uplink 3 and the router, and
other times between the router and LAN hosts.
Ok...
Can we have some information about the IP addresses used for each
network? Do all four networks have IP addresses in different subnets /
networks? Can we ask what they are (sanitized if need be) for the sake
of discussion?
I think that I need to configure something in eth3 config files
(/proc/sys/net/ipv4/conf/eth3) to disallow local frames and allow
only the router and uplink 3 gateway comunication, but I don't found
anything that help me.
I can't say one way or the other for sure until I know what IP addresses
you have where. However as a general rule of thumb you don't need to do
that. I'd be wondering if you don't have a hardware resource / IRQ
conflict depending on how much data (amount and / or size of packets).
I tried with arp_filter, rp_filter, and many of them, but without
success (I don't found many documentation about it, and I review
lartc and googled about that parameters).
I think that only allowing arp traffic betwen eth3 and uplink 3
gateway (using arptables) will solve this, but I don't know if
arptables will be the solution or not.
With out knowing your IP addressing scheme better it's hard to say.
Grant. . . .
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how about doing something to work around the problem
eg
http://computers.search.ebay.com.au/dual-port_Network-Interface-Cards_W0QQdfspZ1QQsacatZ20318
care needed to find one driven by linux. :-)
regards
Brian
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