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wilf
Tux's lil' helper
Joined: 12 Feb 2006
Posts: 131
Location: West Sussex, UK
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 Posted: Tue May 15, 2007 11:55 pm Post subject: [SOLVED] Routing... |
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Hello,
I have built a box for a customer which has the following static ip setupin /etc/conf.d/net.eth0
| Code: | vm-host conf.d # cat net.eth0
modules=("ifconfig" )
config_eth0=( "10.0.253.72 netmask 255.255.0.0 broadcast 10.0.253.255" )
routes_eth0=( "10.0.253.0/24 via 10.0.254.2" ) |
When the machine is booted up, you get this:- | Code: | vm-host ipv4 # route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.253.133 0.0.0.0 255.255.255.255 UH 0 0 0 venet0
10.0.253.0 10.0.254.2 255.255.255.0 UG 0 0 0 eth0
10.0.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo |
What I really want is this | Code: | vm-host ipv4 # route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.253.133 0.0.0.0 255.255.255.255 UH 0 0 0 venet0
10.0.253.0 10.0.254.2 255.255.255.0 UG 0 0 0 eth0
10.0.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 10.0.254.2 0.0.0.0 UG 0 0 0 eth0 |
To get this this, I have to do a | Code: | | route add default gw 10.0.254.2 dev eth0 |
after booting. I thought the line | Code: | | routes_eth0=( "10.0.253.0/24 via 10.0.254.2" ) |
did this in net.eth0. Please will you show me how to get the bottom routing table by correctly configuring net.eth0 so that I don't have to run that route command after booting.
Best Regards, Paul.
Last edited by wilf on Wed May 16, 2007 4:42 pm; edited 1 time in total |
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think4urs11
Bodhisattva
Joined: 25 Jun 2003
Posts: 6659
Location: above the cloud
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| Posted: Wed May 16, 2007 3:44 am Post subject: |
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The netmask and the broadcast address do not match.
Either the netmask is 255.255.255.0 or the broadcast is 10.0.255.255; the combination shown makes no sense.
As the machine itself is in 10.0.253.0/24 the route is completely unneeded; it should be generated automagically anyhow.
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Nothing is secure / Security is always a trade-off with usability / Do not assume anything / Trust no-one, nothing / Paranoia is your friend / Think for yourself |
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erik258
Advocate
Joined: 12 Apr 2005
Posts: 2650
Location: Twin Cities, Minnesota, USA
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| Posted: Wed May 16, 2007 3:50 am Post subject: |
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routes_eth0=(" default via 10.0.254.2" )
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Configuring a Firewall? Try my iptables configuration
LinuxCommando.com is my blog for linux-related scraps and tidbits. Stop by for a visit! |
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wilf
Tux's lil' helper
Joined: 12 Feb 2006
Posts: 131
Location: West Sussex, UK
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| Posted: Wed May 16, 2007 4:42 pm Post subject: |
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Hello Think4UrS11 and erik258,
I have modified the base instance ( the machine is running OpenVZ) and incorporated both your observations - with success.
| Code: | config_eth0=( "10.0.253.72 netmask 255.255.0.0 broadcast 10.0.255.255" )
routes_eth0=("-net 10.0.253.0/24" "default via 10.0.254.2" ) |
So thank you both very much.
I must say with a name like Think4UrS11 I did feel guilty for asking 
I have other problems within the live instance, so I am off to the OpenVZ forums.
Hey ho, Hey Ho, it's off to work I go...
Best Regards, Paul. |
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erik258
Advocate
Joined: 12 Apr 2005
Posts: 2650
Location: Twin Cities, Minnesota, USA
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| Posted: Wed May 16, 2007 8:57 pm Post subject: |
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| Think4UrS11 wrote: | The netmask and the broadcast address do not match.
Either the netmask is 255.255.255.0 or the broadcast is 10.0.255.255; the combination shown makes no sense.
As the machine itself is in 10.0.253.0/24 the route is completely unneeded; it should be generated automagically anyhow. |
Yes, I tripped over this as well. I went with the assumption that there could be a network 10.0/16, and within that a subnet 10.0.0/24. Of course, this means that the subnets' host ip ranges overlap a little, but that shouldn't be a problem until they start conflicting. At least, anything on 10.0/16 with an address of 10.0.0,xx certainly is going to look like it's on both subnets.
I don't know whether this is a good idea, but I wanted to give wilf the benefit of the doubt.
| Code: | | As the machine itself is in 10.0.253.0/24 the route is completely unneeded; it should be generated automagically anyhow. |
Quite so. I was going to say so, but then looked closely and realized that 10.0.253.72/16 isn't on that subnet, so you'll still need a route to 10.0.0/24. The router is on 10.0/16 of course, and that route will be set up automatically by the config_eth0 line.
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Configuring a Firewall? Try my iptables configuration
LinuxCommando.com is my blog for linux-related scraps and tidbits. Stop by for a visit! |
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