[opensuse] DHCP and routing questions
Hello, I want to increase my subnet from 254 usable addresses to 512, however I want to keep the 192.168 20.x range and span the range from 192.168.19.x to 192.168.20.x, while keeping everything on the same subnet. I have static addresses from 20.1 to 20.61. Could I keep it all on the same subnet by making the subnet 192.168.19.0/255.255.254.0? Also, what would I add to the router? I currently have 192.168.20.0/24 and the router's ip is .20.1. If an dhcp address of 192.168.19.3 is assigned will it fail to get to the network since the router has an address of 20.1? Below is a sample of what I think the dhcpd.conf file should look like. Any recommendations? subnet 192.168.19.0 netmask 255.255.254.0 { default-lease-time 259200; option routers 192.168.20.1; option subnet-mask 255.255.254.0; option broadcast-address 192.168.20.255; ***What would I put here?*** option domain-name "example.com"; option tftp-server-name "192.168.20.2"; next-server 192.168.20.2; option domain-name-servers 192.168.20.2; option netbios-name-servers 192.168.20.2; option ntp-servers 192.168.20.2; option time-offset -28800; range dynamic-bootp 192.168.19.2 192.169.19.254; range dynamic-bootp 192.168.20.62 192.168.20.254; <snip> Many thanks, James -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
James D. Parra wrote:
Hello,
I want to increase my subnet from 254 usable addresses to 512, however I want to keep the 192.168 20.x range and span the range from 192.168.19.x to 192.168.20.x, while keeping everything on the same subnet. I have static addresses from 20.1 to 20.61. Could I keep it all on the same subnet by making the subnet 192.168.19.0/255.255.254.0?
You'd have better luck using 192.168.21.x rather than .19.x. To see why, break down the number into binary. 20 in binary is 00010100, 21 is 00010101 and 19 is 00010011. This means that you can't use the same subnet mask for 19 & 20, as the 5th bit is different and you cannot have different addresses for the network portion of the address. You can use 20 & 21 for the same mask of 255.255.254.0 or /23, as only the last bit changes and with the new mask, that bit becomes part of the host address.
Also, what would I add to the router? I currently have 192.168.20.0/24 and the router's ip is .20.1. If an dhcp address of 192.168.19.3 is assigned will it fail to get to the network since the router has an address of 20.1?
Use .21 instead of .19 and you won't have that problem.
Below is a sample of what I think the dhcpd.conf file should look like. Any recommendations?
subnet 192.168.19.0 netmask 255.255.254.0 { default-lease-time 259200; option routers 192.168.20.1; option subnet-mask 255.255.254.0; option broadcast-address 192.168.20.255; ***What would I put here?*** option domain-name "example.com"; option tftp-server-name "192.168.20.2"; next-server 192.168.20.2; option domain-name-servers 192.168.20.2; option netbios-name-servers 192.168.20.2; option ntp-servers 192.168.20.2; option time-offset -28800; range dynamic-bootp 192.168.19.2 192.169.19.254; range dynamic-bootp 192.168.20.62 192.168.20.254; <snip>
Many thanks,
James
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On Tue, 29 Jul 2008 05:02:21 James D. Parra wrote:
Hello,
I want to increase my subnet from 254 usable addresses to 512, however I want to keep the 192.168 20.x range and span the range from 192.168.19.x to 192.168.20.x, while keeping everything on the same subnet. I have static addresses from 20.1 to 20.61. Could I keep it all on the same subnet by making the subnet 192.168.19.0/255.255.254.0?
Also, what would I add to the router? I currently have 192.168.20.0/24 and the router's ip is .20.1. If an dhcp address of 192.168.19.3 is assigned will it fail to get to the network since the router has an address of 20.1?
Below is a sample of what I think the dhcpd.conf file should look like. Any recommendations?
subnet 192.168.19.0 netmask 255.255.254.0 { default-lease-time 259200; option routers 192.168.20.1; option subnet-mask 255.255.254.0; option broadcast-address 192.168.20.255; ***What would I put here?*** option domain-name "example.com"; option tftp-server-name "192.168.20.2"; next-server 192.168.20.2; option domain-name-servers 192.168.20.2; option netbios-name-servers 192.168.20.2; option ntp-servers 192.168.20.2; option time-offset -28800; range dynamic-bootp 192.168.19.2 192.169.19.254; range dynamic-bootp 192.168.20.62 192.168.20.254; <snip>
Many thanks,
James
James, Go to http://www.subnetonline.com and plug in the numbers. You'll see that with an address of 192.168.19.1 and a subnet of 255.255.254.0 the network begins at 192.168.18.1 with the last host being 192.169.19.254. The broadcast address is 192.168.19.255. There are a number of other online subnet calculators to make life easier. Try googling "subnet calculator" - that's how I found the above link. Regards, -- =================================================== Rodney Baker VK5ZTV rodney.baker@iinet.net.au =================================================== In Tulsa, Oklahoma, it is against the law to open a soda bottle without the supervision of a licensed engineer.
participants (3)
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James D. Parra
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James Knott
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Rodney Baker