Re: [opensuse] running out of IP addresses for DHCP
On Feb 3, 2008 5:27 PM, James D. Parra
Hello,
I'd like to expand the pool of addresses DHCP hands out from, 192.168.2.0/255.255.255.0 to 192.168.0.0/255.255.255.0, however I am not sure how to do this correctly. Hi James... if you write that you want to expand the address pool (now 192.168.2.0 mask 255.255.255.0 aka /24 on Cisco notation) to 192.168.0.0 mask 255.255.255.0 aka /24 again, there must be something to understand better... because:
192.168.2.0/24 is a network of 253 Ip address, plus the network and the broadcast address. 192.168.0.0/24 is a network of 253 Ip address, plus the network and the broadcast address. so you are not going to expand your pool but just moving it... Reading your request of reservation for some ip addresses you need, I assume that you want to change the ip address pool in. 192.168.0.0 mask 255.255.0.0 aka /16 that is a B class network, capable of 65534 Ip address (that I assume are a bit too much for you, right??) Beside this, if you want a B class private address pool, you should consider that it shoudn't be a 192.168.x.x network, because it's reserved for C class only. I quote from http://en.wikipedia.org/wiki/Network_class: 172.16.0.0 - 172.31.255.255 (172.16.0.0/12) Private IP addresses, RFC 1918, B Class. This way you can declare for example the 172.16.0.0/23 (mask 255.255.254.0) that has twice IPs than a C class network (510 Ips, with 172.16.0.0 as network address and 172.16.1.255 as broadcast address) or you can declare 172.16.0.0/22 (mask 255.255.252.0) that is 4 times a C class network (1022 IPs, with 172.16.0.0 as network address and 172.16.3.255 as broadcast address) This should better fit your needs and respects the RFC 1918 (http://tools.ietf.org/html/rfc1918) Going trough the configuration of your dhcpd.conf file I would change in: shared-network MY_DOMAIN { subnet 172.16.0.0 netmask 255.255.254.0 { default-lease-time 259200; option routers 172.16.0.1; #assuming you will move there the router address.... option subnet-mask 255.255.254.0; option broadcast-address 172.16.1.255; option domain-name "mydomain.com"; option domain-name-servers 172.16.0.2; # I assume you will migrate the DNS, NTP and NetBios servers here option netbios-name-servers 172.16.0.2; # option ntp-servers 172.16.0.2; # option time-offset -28800; } I hope that this helps a bit! P.S. If you don't want to make so much changes on your environment, consider about adding another C Class to the already working one and route it trough a router. So you will be able to share the workstation on those two networks and keep the existing evironment unchanged... Cheers! AleXX
Also, I'd like to remove the ranges of 192.168.2.0, 192.168.3.0 & 192.168.23.0, from the DHCP pool so I can reserve these ranges for manual assignments.
Currently my dhcpd.conf files has this;
shared-network MY_DOMAIN {
subnet 192.168.2.0 netmask 255.255.255.0 { default-lease-time 259200; option routers 192.168.2.1; option subnet-mask 255.255.255.0; option broadcast-address 192.168.2.255; option domain-name "mydomain.com"; option domain-name-servers 192.168.2.2; option netbios-name-servers 192.168.2.2; option ntp-servers 192.168.2.2; option time-offset -28800; range dynamic-bootp 192.168.2.62 192.168.2.66; range dynamic-bootp 192.168.2.68 192.168.2.71; range dynamic-bootp 192.168.2.73 192.168.2.107; range dynamic-bootp 192.168.2.109 192.168.2.129; range dynamic-bootp 192.168.2.131 192.168.2.133; range dynamic-bootp 192.168.2.135 192.168.2.137; range dynamic-bootp 192.168.2.139 192.168.2.153; range dynamic-bootp 192.168.2.155 192.168.2.157; range dynamic-bootp 192.168.2.159 192.168.2.175; range dynamic-bootp 192.168.2.177 192.168.2.253; }
How can I properly expand the range?
Thank you in advance,
James -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
-- AleXX(R) - Alessandro ICQ: 17197836 MSN: AleXX-77@HotMail.it Skype: AleXX-77 -- AleXX(R) - Alessandro ICQ: 17197836 MSN: AleXX-77@HotMail.it Skype: AleXX-77 -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
AleXX® wrote:
Reading your request of reservation for some ip addresses you need, I assume that you want to change the ip address pool in. 192.168.0.0 mask 255.255.0.0 aka /16 that is a B class network, capable of 65534 Ip address (that I assume are a bit too much for you, right??) Beside this, if you want a B class private address pool, you should consider that it shoudn't be a 192.168.x.x network, because it's reserved for C class only.
I quote from http://en.wikipedia.org/wiki/Network_class: 172.16.0.0 - 172.31.255.255 (172.16.0.0/12) Private IP addresses, RFC 1918, B Class.
IP address classes have been depreciated for many years, in favour of Classless Inter-Domain Routing (CIDR), where you specify the subnet mask directly, instead of relying on address ranges. http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing This means it is entirely permissible to have subnets greater than 256 addresses in the 192.168.x.x range. So, please forget about Class A, B or C addresses. They're no longer relevant. -- Use OpenOffice.org http://www.openoffice.org -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Feb 3, 2008 6:37 PM, James Knott
I quote from http://en.wikipedia.org/wiki/Network_class: 172.16.0.0 - 172.31.255.255 (172.16.0.0/12) Private IP addresses, RFC 1918, B Class.
IP address classes have been depreciated for many years, in favour of Classless Inter-Domain Routing (CIDR), where you specify the subnet mask directly, instead of relying on address ranges. http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing This means it is entirely permissible to have subnets greater than 256 addresses in the 192.168.x.x range. So, please forget about Class A, B or C addresses. They're no longer relevant.
Wow James!! You are totally right!! It was also written in the link I've posted (http://en.wikipedia.org/wiki/Network_class) "Classful networking is obsolete on the modern Internet. There is no longer any such thing as a class A/B/C network. The correct modern representation for what would have been referred to as a "Class B" prior to 1993 would be "a set of /16 addresses", under the Classless Inter-Domain Routing (CIDR) system." It seems I've had a looong "nap" and they "changed the rules" :) Thank you for point this out! Bye! AleXX -- AleXX(R) - Alessandro ICQ: 17197836 MSN: AleXX-77@HotMail.it Skype: AleXX-77 -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Sunday 03 February 2008 09:37, James Knott wrote:
...
IP address classes have been depreciated for many years, in favour of Classless Inter-Domain Routing (CIDR), where you specify the subnet mask directly, instead of relying on address ranges. http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing This means it is entirely permissible to have subnets greater than 256 addresses in the 192.168.x.x range. So, please forget about Class A, B or C addresses. They're no longer relevant.
While that's true, the private ranges defined in the pertinent specification don't allow arbitrary subnet masks nor arbitrary network numbers. According to RFC 1918 (a "Best Current Practice" RFC): 3. Private Address Space The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets: 10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) We will refer to the first block as "24-bit block", the second as "20-bit block", and to the third as "16-bit" block. Note that (in pre-CIDR notation) the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and third block is a set of 256 contiguous class C network numbers. Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Randall R Schulz wrote:
On Sunday 03 February 2008 09:37, James Knott wrote:
...
IP address classes have been depreciated for many years, in favour of Classless Inter-Domain Routing (CIDR), where you specify the subnet mask directly, instead of relying on address ranges. http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing This means it is entirely permissible to have subnets greater than 256 addresses in the 192.168.x.x range. So, please forget about Class A, B or C addresses. They're no longer relevant.
While that's true, the private ranges defined in the pertinent specification don't allow arbitrary subnet masks nor arbitrary network numbers. According to RFC 1918 (a "Best Current Practice" RFC):
3. Private Address Space
The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:
10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
We will refer to the first block as "24-bit block", the second as "20-bit block", and to the third as "16-bit" block. Note that (in pre-CIDR notation) the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and third block is a set of 256 contiguous class C network numbers.
Randall Schulz
I don't see how the above is relevant to the discussion. It's doing nothing more than describing the available private network ranges and not how they're used. That is, if you're hiding behind a NAT router, your addresses must use the above ranges. It does not say you can only use 24 bit sub net masks on your local 192.168.x.x network, as would be implied by a Class C address. -- Use OpenOffice.org http://www.openoffice.org -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
participants (3)
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AleXX® -
James Knott -
Randall R Schulz