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Tag Archive for ip-address

Finding next free IP in a network

I have an IP network and want to automatically find a free IP address to provision a new server. Due to frequent server additions/removals the used IPs might be quite fragmented over the whole address space. To effectively check if an IP is free I have to ping and ask the DNS system, which is considered expensive. So I want to minimise these lookups and store some information about used/free addresses in a relational database. This should give me good candidates and I only have to do a few such lookups.

Finding next free IP in a network

I have an IP network and want to automatically find a free IP address to provision a new server. Due to frequent server additions/removals the used IPs might be quite fragmented over the whole address space. To effectively check if an IP is free I have to ping and ask the DNS system, which is considered expensive. So I want to minimise these lookups and store some information about used/free addresses in a relational database. This should give me good candidates and I only have to do a few such lookups.

listening to packets in promiscuous mode

I am working on an application that get packets that don’t belong to the pc,so i use promiscuous mode on my NIC,i need to read the packet and and handle it.

listening to packets in promiscuous mode

I am working on an application that get packets that don’t belong to the pc,so i use promiscuous mode on my NIC,i need to read the packet and and handle it.

Socket Connecting to Large number of IPs

I have a text file of ~600 CIDR notation IP blocks which, when expanded, amount to ~17.5M IP addresses. I need to socket connect to each one. If it connects, I add it to a “live” list, if it returns an error/refusal, to a “dead” list. Then the socket is closed. I don’t need to read from it, I don’t need to write to it. Obviously, this is a problem of scale, if we generously assume that the connection takes only one second to return success or failure, it would take months to complete, but likely several years. I need to get it down to <24 hours.

Socket Connecting to Large number of IPs

I have a text file of ~600 CIDR notation IP blocks which, when expanded, amount to ~17.5M IP addresses. I need to socket connect to each one. If it connects, I add it to a “live” list, if it returns an error/refusal, to a “dead” list. Then the socket is closed. I don’t need to read from it, I don’t need to write to it. Obviously, this is a problem of scale, if we generously assume that the connection takes only one second to return success or failure, it would take months to complete, but likely several years. I need to get it down to <24 hours.