stoke
Honorary Master
Franks Landy. Luckily I don't cross post all that often.
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What a joke... assigned an invalid IP
- Thread starter JTech
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LandyMan
Honorary Master
stoke
Honorary Master
Hey ... angry clothes have right as well.
LandyMan
Honorary Master
The_Unbeliever
Honorary Master
To add my 2c... an address ending in 255 (and even .0) is perfectly valid depending on the subnet mask.
It's badly written software that causes issues with these addresses because they assume that an IP is always in a Class C network - and you know that assumption is the father of all muckups.
We've specifically had to exclude .0 and .255 in our huge ass DHCP subnet at work because of this.
Oh yeah - and I've got a bigger winky than all of you!
It's badly written software that causes issues with these addresses because they assume that an IP is always in a Class C network - and you know that assumption is the father of all muckups.
We've specifically had to exclude .0 and .255 in our huge ass DHCP subnet at work because of this.
Oh yeah - and I've got a bigger winky than all of you!
I meant to convey that, as the link did work. The http server on the line was active all the time. I couldn't SSH in, as the program would bomb with that IP address, and I couldn't get my mail, as Outlook Express would also similarly bomb with an error.
I am tired of being told i am a fool, when I do know what's cutting to a large degree, but have a different way of expressing myself. If I was a fool, then how come it all works at home, and continues to for years. How come then I can do some funky **** with my toys. People call me a fool un-necessarily are going to get dissed, I feel I am in my right to do so if people diss me for no good reason.
As for saying it's badly written software, I can agree with that to an extent, because it was NOT THE LINK, it was the apps that failed they refused to connect.
I am aware of this and implemented it in my own DHCP scheme, which arguably is much smaller, only going up to 54 odd available addresses.
I just felt that iBurst shouldn't allocate IP's like that, because it costs me time and petrol to drive out all the way to go and reset the thing so it picks a better IP.
who.is.michael
Expert Member
who.is.michael
Expert Member
PM me and I'll guide you...
Just so you know...
Internet Protocol (IP) Addresses
Because TCP/IP networks are interconnected across the world, each computer on the Internet must have a unique address (called an IP address) to make sure that transmitted data reaches the correct destination. Blocks of addresses are assigned to organizations by the Internet Assigned Numbers Authority (IANA). Individual users and small organizations may obtain their addresses either from the IANA or from an Internet service provider (ISP). You can contact IANA at http://www.iana.org.
The Internet Protocol (IP) uses a 32-bit address structure. The address is usually written in dot notation (also called dotted-decimal notation), in which each group of eight bits is written indecimal form, separated by decimal points.
For example, the following binary address:
11000011 00100010 00001100 00000111 is normally written as: 195.34.12.7
The latter version is easier to remember and easier to enter into your computer. In addition, the 32 bits of the address are subdivided into two parts. The first part of the address identifies the network, and the second part identifies the host node or station on the network. The dividing point may vary depending on the address range and the application.
There are five standard classes of IP addresses.
These address classes have different ways of determining the network and host sections of the address, allowing for different numbers of hosts on a network.
Each address type begins with a unique bit pattern, which is used by the TCP/IP software to identify the address class. After the address class has been determined, the software can correctly identify the host section of the address.
The five address classes are:
• Class A
Class A addresses can have up to 16,777,214 hosts on a single network. They use an 8-bit network number and a 24-bit node number. Class A addresses are in this range:
1.x.x.x to 126.x.x.x.
• Class B
Class B addresses can have up to 65,354 hosts on a network. A Class B address uses a 16-bit network number and a 16-bit node number. Class B addresses are in this range:
128.1.x.x to 191.254.x.x.
• Class C
Class C addresses can have up to 254 hosts on a network. A Class C address uses a 24-bit network number and an 8-bit node number. Class C addresses are in this range:
192.0.1.x to 223.255.254.x.
• Class D
Class D addresses are used for multicasts (messages sent to many hosts). Class D addresses are in this range:
224.0.0.0 to 239.255.255.255.
• Class E
Class E addresses are for experimental use.
This addressing structure allows IP addresses to uniquely identify each physical network and each node on each physical network. For each unique value of the network portion of the address, the base address of the range (host address of all zeros) is known as the network address and is not usually assigned to a host. Also, the top address of the range (host address of all ones) is not assigned, but is used as the broadcast address for simultaneously sending a packet to all hosts with the same network address.
Netmask
In each of the address classes previously described, the size of the two parts (network address and host address) is implied by the class. This partitioning scheme can also be expressed by a netmask associated with the IP address. A netmask is a 32-bit quantity that, when logically combined (using an AND operator) with an IP address, yields the network address. For instance, the netmasks for Class A, B, and C addresses are 255.0.0.0, 255.255.0.0, and 255.255.255.0, respectively.
For example, the address 192.168.170.237 is a Class C IP address whose network portion is the upper 24 bits. When combined (using an AND operator) with the Class C netmask, as shown here, only the network portion of the address remains:
11000000 10101000 10101010 11101101 (192.168.170.237)
combined with:
11111111 11111111 11111111 00000000 (255.255.255.0)
equals:
11000000 10101000 10101010 00000000 (192.168.170.0)
As a shorter alternative to dotted-decimal notation, the netmask may also be expressed in terms of the number of ones from the left. This number is appended to the IP address, following a backward slash (/), as “/n.” In the example, the address could be written as 192.168.170.237/24, indicating that the netmask is 24 ones followed by 8 zeros.
Subnet Addressing
By looking at the addressing structures, you can see that even with a Class C address, there are a large number of hosts per network. Such a structure is an inefficient use of addresses if each end of a routed link requires a different network number. It is unlikely that the smaller office LANs would have that many devices. You can resolve this problem by using a technique known as subnet addressing.
Subnet addressing allows us to split one IP network address into smaller multiple physical networks known as subnetworks. Some of the node numbers are used as a subnet number instead. A Class B address gives us 16 bits of node numbers translating to 64,000 nodes. Most organizations do not use 64,000 nodes, so there are free bits that can be reassigned. Subnet addressing makes use of those bits that are free, as shown below.
A Class B address can be effectively translated into multiple Class C addresses. For example, the IP address of 172.16.0.0 is assigned, but node addresses are limited to 255 maximum, allowing eight extra bits to use as a subnet address. The IP address of 172.16.97.235 would be interpreted as IP network address 172.16, subnet number 97, and node number 235. In addition to extending the number of addresses available, subnet addressing provides other benefits.
Subnet addressing allows a network manager to construct an address scheme for the network by using different subnets for other geographical locations in the network or for other departments in the organization.
Although the preceding example uses the entire third octet for a subnet address, note that you are not restricted to octet boundaries in subnetting.
To create more network numbers, you need only shift some bits from the host address to the network address. For instance, to partition a Class C network number (192.68.135.0) into two, you shift one bit from the host address to the network address. The new netmask (or subnet mask) is 255.255.255.128.
The first subnet has network number 192.68.135.0 with hosts 192.68.135.1 to 129.68.135.126, and the second subnet has network number 192.68.135.128 with hosts 192.68.135.129 to 192.68.135.254.
Note: The number 192.68.135.127 is not assigned because it is the broadcast address of the first subnet. The number 192.68.135.128 is not assigned because it is the network address of the second subnet.
The following table lists the additional subnet mask bits in dotted-decimal notation. To use the table, write down the original class netmask and replace the 0-value octets with the dotted-decimal value of the additional subnet bits. For example, to partition your Class C network with subnet mask 255.255.255.0 into 16 subnets (four bits), the new subnet mask becomes 255.255.255.240.
The following table displays several common netmask values in both the dotted-decimal and the masklength formats.
Configure all hosts on a LAN segment to use the same netmask for the following reasons:
Netmask Notation Translation Table for One Octet
Number of Bits /Dotted-Decimal Value
1 /128
2 /192
3 /224
4 /240
5 /248
6 /252
7 /254
8 /255
Netmask Formats
Dotted-Decimal /Masklength
255.0.0.0 /8
255.255.0.0 /16
255.255.255.0 /24
255.255.255.128 /25
255.255.255.192 /26
255.255.255.224 /27
255.255.255.240 /28
255.255.255.248 /29
255.255.255.252 /30
255.255.255.254 /31
255.255.255.255 /32
• So that hosts recognize local IP broadcast packets When a device broadcasts to its segment neighbors, it uses a destination address of the local network address with all ones for the host address. In order for this scheme to work, all devices on the segment must agree on which bits comprise the host address.
• So that a local router or bridge recognizes which addresses are local and which are remote Private IP Addresses If your local network is isolated from the Internet (for example, when using Network Address Translation, NAT, which is described below), you can assign any IP addresses to the hosts without problems.
However, the IANA has reserved the following three blocks of IP addresses specifically for private networks:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
Choose your private network number from this range. Some products have DHCP servers that are preconfigured to automatically assign private addresses. Regardless of your particular situation, do not create an arbitrary IP address; always follow the guidelines.
For more information about address assignment, refer to RFC 1597, Address Allocation for Private Internets, and RFC 1466, Guidelines for Management of IP Address Space. The Internet Engineering Task Force (IETF) publishes RFCs on its Web site at http://www.ietf.org.
Published by Netgear (TCPIP Networking)
Just so you know...
Internet Protocol (IP) Addresses
Because TCP/IP networks are interconnected across the world, each computer on the Internet must have a unique address (called an IP address) to make sure that transmitted data reaches the correct destination. Blocks of addresses are assigned to organizations by the Internet Assigned Numbers Authority (IANA). Individual users and small organizations may obtain their addresses either from the IANA or from an Internet service provider (ISP). You can contact IANA at http://www.iana.org.
The Internet Protocol (IP) uses a 32-bit address structure. The address is usually written in dot notation (also called dotted-decimal notation), in which each group of eight bits is written indecimal form, separated by decimal points.
For example, the following binary address:
11000011 00100010 00001100 00000111 is normally written as: 195.34.12.7
The latter version is easier to remember and easier to enter into your computer. In addition, the 32 bits of the address are subdivided into two parts. The first part of the address identifies the network, and the second part identifies the host node or station on the network. The dividing point may vary depending on the address range and the application.
There are five standard classes of IP addresses.
These address classes have different ways of determining the network and host sections of the address, allowing for different numbers of hosts on a network.
Each address type begins with a unique bit pattern, which is used by the TCP/IP software to identify the address class. After the address class has been determined, the software can correctly identify the host section of the address.
The five address classes are:
• Class A
Class A addresses can have up to 16,777,214 hosts on a single network. They use an 8-bit network number and a 24-bit node number. Class A addresses are in this range:
1.x.x.x to 126.x.x.x.
• Class B
Class B addresses can have up to 65,354 hosts on a network. A Class B address uses a 16-bit network number and a 16-bit node number. Class B addresses are in this range:
128.1.x.x to 191.254.x.x.
• Class C
Class C addresses can have up to 254 hosts on a network. A Class C address uses a 24-bit network number and an 8-bit node number. Class C addresses are in this range:
192.0.1.x to 223.255.254.x.
• Class D
Class D addresses are used for multicasts (messages sent to many hosts). Class D addresses are in this range:
224.0.0.0 to 239.255.255.255.
• Class E
Class E addresses are for experimental use.
This addressing structure allows IP addresses to uniquely identify each physical network and each node on each physical network. For each unique value of the network portion of the address, the base address of the range (host address of all zeros) is known as the network address and is not usually assigned to a host. Also, the top address of the range (host address of all ones) is not assigned, but is used as the broadcast address for simultaneously sending a packet to all hosts with the same network address.
Netmask
In each of the address classes previously described, the size of the two parts (network address and host address) is implied by the class. This partitioning scheme can also be expressed by a netmask associated with the IP address. A netmask is a 32-bit quantity that, when logically combined (using an AND operator) with an IP address, yields the network address. For instance, the netmasks for Class A, B, and C addresses are 255.0.0.0, 255.255.0.0, and 255.255.255.0, respectively.
For example, the address 192.168.170.237 is a Class C IP address whose network portion is the upper 24 bits. When combined (using an AND operator) with the Class C netmask, as shown here, only the network portion of the address remains:
11000000 10101000 10101010 11101101 (192.168.170.237)
combined with:
11111111 11111111 11111111 00000000 (255.255.255.0)
equals:
11000000 10101000 10101010 00000000 (192.168.170.0)
As a shorter alternative to dotted-decimal notation, the netmask may also be expressed in terms of the number of ones from the left. This number is appended to the IP address, following a backward slash (/), as “/n.” In the example, the address could be written as 192.168.170.237/24, indicating that the netmask is 24 ones followed by 8 zeros.
Subnet Addressing
By looking at the addressing structures, you can see that even with a Class C address, there are a large number of hosts per network. Such a structure is an inefficient use of addresses if each end of a routed link requires a different network number. It is unlikely that the smaller office LANs would have that many devices. You can resolve this problem by using a technique known as subnet addressing.
Subnet addressing allows us to split one IP network address into smaller multiple physical networks known as subnetworks. Some of the node numbers are used as a subnet number instead. A Class B address gives us 16 bits of node numbers translating to 64,000 nodes. Most organizations do not use 64,000 nodes, so there are free bits that can be reassigned. Subnet addressing makes use of those bits that are free, as shown below.
A Class B address can be effectively translated into multiple Class C addresses. For example, the IP address of 172.16.0.0 is assigned, but node addresses are limited to 255 maximum, allowing eight extra bits to use as a subnet address. The IP address of 172.16.97.235 would be interpreted as IP network address 172.16, subnet number 97, and node number 235. In addition to extending the number of addresses available, subnet addressing provides other benefits.
Subnet addressing allows a network manager to construct an address scheme for the network by using different subnets for other geographical locations in the network or for other departments in the organization.
Although the preceding example uses the entire third octet for a subnet address, note that you are not restricted to octet boundaries in subnetting.
To create more network numbers, you need only shift some bits from the host address to the network address. For instance, to partition a Class C network number (192.68.135.0) into two, you shift one bit from the host address to the network address. The new netmask (or subnet mask) is 255.255.255.128.
The first subnet has network number 192.68.135.0 with hosts 192.68.135.1 to 129.68.135.126, and the second subnet has network number 192.68.135.128 with hosts 192.68.135.129 to 192.68.135.254.
Note: The number 192.68.135.127 is not assigned because it is the broadcast address of the first subnet. The number 192.68.135.128 is not assigned because it is the network address of the second subnet.
The following table lists the additional subnet mask bits in dotted-decimal notation. To use the table, write down the original class netmask and replace the 0-value octets with the dotted-decimal value of the additional subnet bits. For example, to partition your Class C network with subnet mask 255.255.255.0 into 16 subnets (four bits), the new subnet mask becomes 255.255.255.240.
The following table displays several common netmask values in both the dotted-decimal and the masklength formats.
Configure all hosts on a LAN segment to use the same netmask for the following reasons:
Netmask Notation Translation Table for One Octet
Number of Bits /Dotted-Decimal Value
1 /128
2 /192
3 /224
4 /240
5 /248
6 /252
7 /254
8 /255
Netmask Formats
Dotted-Decimal /Masklength
255.0.0.0 /8
255.255.0.0 /16
255.255.255.0 /24
255.255.255.128 /25
255.255.255.192 /26
255.255.255.224 /27
255.255.255.240 /28
255.255.255.248 /29
255.255.255.252 /30
255.255.255.254 /31
255.255.255.255 /32
• So that hosts recognize local IP broadcast packets When a device broadcasts to its segment neighbors, it uses a destination address of the local network address with all ones for the host address. In order for this scheme to work, all devices on the segment must agree on which bits comprise the host address.
• So that a local router or bridge recognizes which addresses are local and which are remote Private IP Addresses If your local network is isolated from the Internet (for example, when using Network Address Translation, NAT, which is described below), you can assign any IP addresses to the hosts without problems.
However, the IANA has reserved the following three blocks of IP addresses specifically for private networks:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
Choose your private network number from this range. Some products have DHCP servers that are preconfigured to automatically assign private addresses. Regardless of your particular situation, do not create an arbitrary IP address; always follow the guidelines.
For more information about address assignment, refer to RFC 1597, Address Allocation for Private Internets, and RFC 1466, Guidelines for Management of IP Address Space. The Internet Engineering Task Force (IETF) publishes RFCs on its Web site at http://www.ietf.org.
Published by Netgear (TCPIP Networking)
Last edited:
Ekhaatvensters
Executive Member
Fanboy.
No really, its a good explanation, thanks.Also, I see it looks like the whole of CPT is now in the 41.208 IP range, so did this solve any remaining dead IP issues?
who.is.michael
Expert Member
But it seems to be somewhat better...
Hi there MrH / EHV
The occurrence of dead IP's seems less frequent than before - have you experienced the same?
Regards
M
I agree EHV, one of the better explanations I've come across, not too technical but still didactic.
Hi there MrH / EHV
The occurrence of dead IP's seems less frequent than before - have you experienced the same?
Regards
M
I agree EHV, one of the better explanations I've come across, not too technical but still didactic.
Last edited:
who.is.michael
Expert Member
I've noticed the same...
Yeah same here.
I've noticed that download speed is much greater on the higher IP's. In the third octet of this IP address 41.208.XXX.XXX, should it be equal to 228 or greater BW throughput is excellent, on condition that the fourth octet is greater than 235.
The best IP I've had is 41.208.238.235 but not often enough, sadly. Currently on 41.208.234.237 and it is delivering BW reading of 1.04 Mbps, but in a few hours it's back to 200 kbps.
ps. you still up?
Yeah same here.
I've noticed that download speed is much greater on the higher IP's. In the third octet of this IP address 41.208.XXX.XXX, should it be equal to 228 or greater BW throughput is excellent, on condition that the fourth octet is greater than 235.
The best IP I've had is 41.208.238.235 but not often enough, sadly. Currently on 41.208.234.237 and it is delivering BW reading of 1.04 Mbps, but in a few hours it's back to 200 kbps.
ps. you still up?
Last edited:
who.is.michael
Expert Member
Ouch, why so few - you must be growing old quite quickly? My excuse is invoicing...