I am new in the mailing list, I've been readin lots of posts seeking an answer to my questions, I hope you can help.
This is the situation:
L R I O eth0--------62.42.XX.XX (assigned by dhcp) (gw assigned 62.42.a.b) N U eth1--------62.42.YY.YY (assigned by dhcp) (gw assigned 62.42.a.b) U T eth2--------62.43.ZZ.ZZ (assigned by dhcp) (gw assigned 62.43.c.d) X E eth3--------172.31.0.254 (manually assigned) (this is the gateway for the LAN) R eth3--------192.168.0.6 (manually assigned) (this is a routers subnet)
Im using iproute2 + fwmark + iptables mark + one table per device with one different gw each) I classify the kind of traffic classifying it in bulk traffic and on-line traffic. As of the nature of the different applications that are run in this place (we are a lot of friends with a place where we play on-line games, just for fun :) ). I do port forwarding through different gateways, I have 5 operating gateways having traffic all the time, One link for p2p, another for ftp downloads, and the rest for playing quake, warcraft, and whatever game is good, I love linux and Im trying to make all them appreciate this fantastic OS ;)
Everything worked fine till we get the modem cable attached to eth1, this modem is from the same ISP than eth0's, and unfortunately, this ISP assigns to eth0 and eth1 the same gateway (62.42.a.b). I've been reading arp flux problem with this kind of troubles, and also the hidden patch but I couldn't make it work.
This is the whole config:
EXTIF1="eth0" EXTIF2="eth1" EXTIF3="eth2" MEDIF="eth3" INTIF="eth4"
GW1 = Gateway of the first cmodem GW2 = Gateway of the second cmodem Gw3 = Gateway of the third cmodem
IP1 = Public IP of eth0 IP2 = Public IP of eth1 IP3 = Public IP of eth2
Create the tables for each route:
echo 255 local > /etc/iproute2/rt_tables echo 254 main >> /etc/iproute2/rt_tables echo 253 default >> /etc/iproute2/rt_tables echo 0 unspec >> /etc/iproute2/rt_tables echo 200 cablemodem1 >> /etc/iproute2/rt_tables echo 201 router1 >> /etc/iproute2/rt_tables echo 202 router2 >> /etc/iproute2/rt_tables echo 203 router3 >> /etc/iproute2/rt_tables echo 204 balanceo >> /etc/iproute2/rt_tables echo 205 cablemodem2 >> /etc/iproute2/rt_tables echo 206 cablemodem3 >> /etc/iproute2/rt_tables
Turn off reverse path filtering
echo "0" > /proc/sys/net/ipv4/conf/eth0/rp_filter echo "0" > /proc/sys/net/ipv4/conf/eth1/rp_filter echo "0" > /proc/sys/net/ipv4/conf/eth2/rp_filter echo "0" > /proc/sys/net/ipv4/conf/eth3/rp_filter
Messing with the arp flux problem (I suppose thats my problem)
echo "0" > /proc/sys/net/ipv4/conf/eth0/hidden echo "0" > /proc/sys/net/ipv4/conf/eth1/hidden
echo "1" > /proc/sys/net/ipv4/conf/eth0/arp_filter echo "1" > /proc/sys/net/ipv4/conf/eth1/arp_filter
Assign fwmark to each table
ip rule add fwmark 1 table router1 ip rule add fwmark 2 table router2 ip rule add fwmark 3 table router3 ip rule add fwmark 4 table balanceo ip rule add fwmark 5 table cablemodem1 ip rule add fwmark 6 table cablemodem2 ip rule add fwmark 7 table cablemodem3
Assign route for each table
ip route add table balanceo eql nexthop via $GW2 dev $EXTIF2 weight 1 nexthop via $GW1 dev $EXTIF1 weight 1 ip route add default via 192.168.0.1 dev $MEDIF src 192.168.0.6 table router1 ip route add default via 192.168.0.2 dev $MEDIF src 192.168.0.6 table router2 ip route add default via 192.168.0.3 dev $MEDIF src 192.168.0.6 table router3 ip route add default via $GW1 dev $EXTIF1 src $IP1 table cablemodem1 ip route add default via $GW2 dev $EXTIF2 src $IP2 table cablemodem2 ip route add default via $GW3 dev $EXTIF3 src $IP3 table cablemodem3
We ensure each interface will put it's own IP
ip route add $GW1 dev $EXTIF1 src $IP1 ip route add $GW2 dev $EXTIF2 src $IP2 ip route add $GW3 dev $EXTIF3 src $IP3
We assign each gw as HOST for those routing tables
ip rule add from $GW1 table cablemodem1 ip rule add from $GW2 table cablemodem2 ip rule add from $GW3 table cablemodem3
I think that it's "a grosso modo" my config
The result of route -n:
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 62.43.c.d 0.0.0.0 255.255.255.255 UH 0 0 0 eth2 62.42.a.b 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 192.168.0.0 0.0.0.0 255.255.255.248 U 0 0 0 eth3 172.31.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth4 62.42.x.y 0.0.0.0 255.255.248.0 U 0 0 0 eth0 62.42.x.y 0.0.0.0 255.255.248.0 U 0 0 0 eth1 62.43.t.z 0.0.0.0 255.255.240.0 U 0 0 0 eth2 0.0.0.0 62.42.a.b 0.0.0.0 UG 0 0 0 eth0
The problem resides in eth0 and eth1, the get exactly the same config, just with different IP address.
xerver:~# ip neigh sh
62.42.a.b dev eth0 lladdr 00:05:31:f8:17:c0 nud stale 62.43.c.d dev eth1 lladdr 00:05:31:f8:17:c0 nud stale
But take a look at this, in the arp cache, the phisical address of the gw is the same for both gw. This is possible because eth0, eth1 and eth2 are from the same ISP. Maybe this isp aliases ip on interfaces for traffic management... (i don't know).
There are a lot of question without answers, I couldn'f find them:
Should I remove the dafult gateway? If I should, how could I make the router itself to reach internet? Maybe marking locally generated packets and assigning a route to that fwmark? I tried this, but no success.
When I run this in my script
ip ro add 62.42.a.b dev eth2 src 62.42.yy.yy RTNETLINK answers: File exists
Ok, thats, because both devices use the same gateway, and so, I suppose a shouldn't univocally bind that address to any? Correct?
I don't know if I'm missing something, Hope u can help me. And lots of thanks for reading until here ;)
Xisco Fernandez
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