netmask

问题 I need to write a bash script that when I enter two ip addresses, it will calculate summarize address for them. Examlpe: 192.168.1.27/25 192.168.1.129/25 Result will be: 192.168.1.0/24 Can you help me with this script? I know you will say to me “What did you try?” I tried to find something in Google, but what I found that I must to convert to binary then calculate it, and it will be very hard. I even don’t know how to start with it. Any idea or hint please? 回答1: Calculation of common netmask

问题 I need to write a bash script that when I enter two ip addresses, it will calculate summarize address for them. Examlpe: 192.168.1.27/25 192.168.1.129/25 Result will be: 192.168.1.0/24 Can you help me with this script? I know you will say to me “What did you try?” I tried to find something in Google, but what I found that I must to convert to binary then calculate it, and it will be very hard. I even don’t know how to start with it. Any idea or hint please? 回答1: Calculation of common netmask

问题 In a bash script I have an IP address like 140.179.220.200 and a netmask like 255.255.224.0. I now want to calculate the Network address(140.179.192.000), first usable Host IP(140.179.192.1), last usable Host IP(140.179.220.254), and the Broadcast Address(140.179.223.255). I was able to find a clean way to do the network address below. I'm able to do subnet calculations by hand, but mainly having difficulties translating that into a bash script. Thanks in advance $ IFS=. read -r i1 i2 i3 i4 <

问题 Does someone have a good example of a way I could take a IP address with a CIDR such as 192.168.1.1/24 and return all the ip addresses inside of that range such as 192.168.1.1, 192.168.1.2, 192.168.1.3 ... I'm fine with it being returned in a array of unsigned long , a char or just something like /* Pseudocode */ while(currnetip <= finalip) { print(currnetip); currnetip++; } As long as I can understand it its fine. Feel free to comment a link to a post if you think it could help me. Edit:

问题 I need to detect the local IP address and subnet mask on the WiFi network, on an Android device (in order to proper calculate the UDP broadcast address strictly for the local subnet). When the device is connected to an Access Point, the following is properly working: // Only works when NOT tethering WifiManager wifi = (WifiManager) context.getSystemService(Context.WIFI_SERVICE); DhcpInfo dhcp = wifi.getDhcpInfo(); if (dhcp == null) throw new IOException("No DHCPInfo on WiFi side."); foo(dhcp

问题 How can I convert a CIDR prefix to a dotted-quad netmask in Python? For example, if the prefix is 12 I need to return 255.240.0.0 . 回答1: You can do it like this: def cidr(prefix): return socket.inet_ntoa(struct.pack(">I", (0xffffffff << (32 - prefix)) & 0xffffffff)) 回答2: Here is a solution on the lighter side (no module dependencies): netmask = '.'.join([str((0xffffffff << (32 - len) >> i) & 0xff) for i in [24, 16, 8, 0]]) 回答3: And this is a more efficient one: netmask = 0xFFFFFFFF & (2**(32

问题 I need help in writing a function in C/C++ that receives two parameters: IP address and subnetmask . The function needs to reutrn a list of all IP addresses that are in the associated network. For example: Given two parameters: IP address = 192.168.33.72 and mask = 255.255.255.192 the function will return a list that contain the IP's 192.168.33.65 to 192.168.33.126. 回答1: 1) first you can transform the ipaddress and the subnetmask from string format to binary format with inet_pton() . 2) make

问题 How do I calculate the number of hosts in a netmask using TSQL, WITHOUT using a table. For example : IP Number of Host 255.255.255.252 = 4 255.255.254.0 = 512 回答1: Here is the SQLFiddel Demo Below is the sample Query : select (256-T.I1)*(256-T.I2)*(256-T.I3)*(256-T.I4) from ( select dbo.fnParseString(-1, '.', IP) 'I1', dbo.fnParseString(-2, '.', IP) 'I2', dbo.fnParseString(-3, '.', IP) 'I3', dbo.fnParseString(-4, '.', IP) 'I4' from (select '255.255.255.252' as IP union select '255.255.254.0')

问题 I'm trying to determine the network segment my Macbook is in, because I then want to scan this segment for active hosts (basic IP scanner) by using the CFHost class. Therefore I need the IP and Netmask of my active interface. This is how I get the IP: NSString *ipAddr = [[[NSHost currentHost] addresses] objectAtIndex:0]; But I have absolutely no idea how to get the Netmask, so I'm kind of stuck. Especially because I'm fairly new at Objective-C and because I also do not have extensive

问题 Our Datacenter has given us a JSON dump from all of our machines to import into our own inventory management system. This supplies the IP Blocks such as (192.168.1.1/26) but as I am importing hundreds of blocks, I would like to also calculate the Netmask and Gateway. I looked over the networking functions on the PHP Doxygen but was not able to find any way to do this. How can I calculate Netmask/Gateway from an IP Block? 回答1: You can calculate the ip and mask using something like this: $ip