I have two interfaces on a centos machine with IPs 192.168.2.15 and 192.168.3.15. The routing table is:
# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.3.0 * 255.255.255.0 U 0 0 0 eth1 192.168.2.0 * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 0 0 0 eth1 default 192.168.2.1 0.0.0.0 UG 0 0 0 eth0
The gateway 192.168.2.1 is a wireless router on which I have a static route for 192.168.3.0/24 to 192.168.2.15.
The problem is I cannot communicate between these networks. If I ping from a machine on 192.168.2.0 to a machine on 192.168.3.0 it never makes it. If I run tcpdump -i eth0 on the machine with two nics, I can see the ICMP packets coming in so I know the static route on the wireless router is working. If I run tcpdump -i eth1 I cannot see the ICMP packets. So the routing is wrong. I can successfully ping the machine on the 192.168.3.0 network from the machine with two interfaces.
I would think that a packet sent from 192.168.2.100 for 192.168.3.128 would go to the gateway, get sent to 192.168.2.15 which it would go though the above listed routing table, match 192.168.3.0 and get sent to eth1. What am I doing wrong?
Mike
Hummh, maybe the following question may seem silly, but have you enabled ip routing on your CentOS box ? What's the result of cat /proc/sys/net/ipv4/ip_forward ? If you have enabled ip routing , maybe have a look at your firewall rules to be sure that you don't drop any packets ...
On Sun, 2006-06-18 at 15:06 -0400, Michael B Allen wrote:
I have two interfaces on a centos machine with IPs 192.168.2.15 and 192.168.3.15. The routing table is:
# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.3.0 * 255.255.255.0 U 0 0 0 eth1 192.168.2.0 * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 0 0 0 eth1 default 192.168.2.1 0.0.0.0 UG 0 0 0 eth0
The gateway 192.168.2.1 is a wireless router on which I have a static route for 192.168.3.0/24 to 192.168.2.15.
The problem is I cannot communicate between these networks. If I ping from a machine on 192.168.2.0 to a machine on 192.168.3.0 it never makes it. If I run tcpdump -i eth0 on the machine with two nics, I can see the ICMP packets coming in so I know the static route on the wireless router is working. If I run tcpdump -i eth1 I cannot see the ICMP packets. So the routing is wrong. I can successfully ping the machine on the 192.168.3.0 network from the machine with two interfaces.
I would think that a packet sent from 192.168.2.100 for 192.168.3.128 would go to the gateway, get sent to 192.168.2.15 which it would go though the above listed routing table, match 192.168.3.0 and get sent to eth1. What am I doing wrong?
Mike
IP routing should be turned off by default. You will also need to edit your /etc/sysctl.conf file so that the line that reads:
net.ipv4.ip_forward=0 reads net.ipv4.ip_forward=1
This will enable IP forwarding on all interfaces; if you want to enable it on just one interface then you will need to remove the previously stated line and add a line in /etc/sysctl.conf that reads:
net.ipv4.conf.<interface>.forwarding=1 ## Replacing interface with the appropriate interface (ex. eth0).
I also want to remind you that enabling ip routing on any interface is a security risk, so be warned.
Also look out for the response from my friend Eric Davis, he is explicitly looking into this just for you; so if you still have issues maybe he can provide some insight.
On 6/18/06, Fabian Arrotin fabian.arrotin@arrfab.net wrote:
Hummh, maybe the following question may seem silly, but have you enabled ip routing on your CentOS box ? What's the result of cat /proc/sys/net/ipv4/ip_forward ? If you have enabled ip routing , maybe have a look at your firewall rules to be sure that you don't drop any packets ...
On Sun, 2006-06-18 at 15:06 -0400, Michael B Allen wrote:
I have two interfaces on a centos machine with IPs 192.168.2.15 and 192.168.3.15. The routing table is:
# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.3.0 * 255.255.255.0 U 0 0 0
eth1
192.168.2.0 * 255.255.255.0 U 0 0 0
eth0
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
default 192.168.2.1 0.0.0.0 UG 0 0 0
eth0
The gateway 192.168.2.1 is a wireless router on which I have a static route for 192.168.3.0/24 to 192.168.2.15.
The problem is I cannot communicate between these networks. If I ping from a machine on 192.168.2.0 to a machine on 192.168.3.0 it never makes it. If I run tcpdump -i eth0 on the machine with two nics, I can see the ICMP packets coming in so I know the static route on the wireless router is working. If I run tcpdump -i eth1 I cannot see the ICMP packets. So
the
routing is wrong. I can successfully ping the machine on the 192.168.3.0 network from the machine with two interfaces.
I would think that a packet sent from 192.168.2.100 for 192.168.3.128 would go to the gateway, get sent to 192.168.2.15 which it would go though the above listed routing table, match 192.168.3.0 and get sent to eth1. What am I doing wrong?
Mike
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CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
My previously stated reply will prevent your system to returning to its previous state after a reboot.
On 6/18/06, Joshua Gimer jgimer@gmail.com wrote:
IP routing should be turned off by default. You will also need to edit your /etc/sysctl.conf file so that the line that reads:
net.ipv4.ip_forward=0 reads net.ipv4.ip_forward=1
This will enable IP forwarding on all interfaces; if you want to enable it on just one interface then you will need to remove the previously stated line and add a line in /etc/sysctl.conf that reads:
net.ipv4.conf.<interface>.forwarding=1 ## Replacing interface with the appropriate interface (ex. eth0).
I also want to remind you that enabling ip routing on any interface is a security risk, so be warned.
Also look out for the response from my friend Eric Davis, he is explicitly looking into this just for you; so if you still have issues maybe he can provide some insight.
On 6/18/06, Fabian Arrotin fabian.arrotin@arrfab.net wrote:
Hummh, maybe the following question may seem silly, but have you enabled
ip routing on your CentOS box ? What's the result of cat /proc/sys/net/ipv4/ip_forward ? If you have enabled ip routing , maybe have a look at your firewall rules to be sure that you don't drop any packets ...
On Sun, 2006-06-18 at 15:06 -0400, Michael B Allen wrote:
I have two interfaces on a centos machine with IPs 192.168.2.15 and 192.168.3.15. The routing table is:
# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.3.0 * 255.255.255.0 U 0 0 0
eth1
192.168.2.0 * 255.255.255.0 U 0 0 0
eth0
169.254.0.0 * 255.255.0.0 U 0 0 0
eth1
default 192.168.2.1 0.0.0.0 UG 0 0 0
eth0
The gateway 192.168.2.1 is a wireless router on which I have a static route for 192.168.3.0/24 to 192.168.2.15.
The problem is I cannot communicate between these networks. If I ping from a machine on 192.168.2.0 to a machine on 192.168.3.0 it never makes it. If I run tcpdump -i eth0 on the machine with two nics, I can see the ICMP packets coming in so I know the static route on the wireless router
is working. If I run tcpdump -i eth1 I cannot see the ICMP packets. So
the
routing is wrong. I can successfully ping the machine on the 192.168.3.0 network from the machine with two interfaces.
I would think that a packet sent from 192.168.2.100 for 192.168.3.128 would go to the gateway, get sent to 192.168.2.15 which it would go though the above listed routing table, match 192.168.3.0 and get sent to eth1. What am I doing wrong?
Mike
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CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
-- Thx Joshua Gimer
On Sun, 18 Jun 2006 19:04:58 -0600 "Joshua Gimer" jgimer@gmail.com wrote:
IP routing should be turned off by default. You will also need to edit your /etc/sysctl.conf file so that the line that reads:
net.ipv4.ip_forward=0 reads net.ipv4.ip_forward=1
This will enable IP forwarding on all interfaces; if you want to enable it on just one interface then you will need to remove the previously stated line and add a line in /etc/sysctl.conf that reads:
net.ipv4.conf.<interface>.forwarding=1 ## Replacing interface with the appropriate interface (ex. eth0).
I bet that's it. I don't recall ever doing this before but then again the previous installation was pretty old (RH 7.2).
Unfortunately I won't know for sure until I rebuild the machine because the disk just died!
Note to self: Don't use an IBM Deskstar from a machine that's been sitting in the attic without air conditioning or heat for 6 years.
:-/
Mike
Note to self: Don't use an IBM Deskstar from a machine that's been sitting in the attic without air conditioning or heat for 6 years.
Haha, must be one of those IBM Deathstars ;)
/me wonders if the smartctl checks did the disk in because certain IBM Deathstars would run fine but self-destruct after a SMART command is issued...
-
Fabian Arrotin -
Feizhou -
Joshua Gimer -
Michael B Allen