We now summarize the important special cases for Class A, B,Īnd C IP addresses, using the following notation for an IPĪnd the notation '-1' for a field that contains all 1 bits. Group membership isĭetermined dynamically using IGMP. Internet Engineering Task Force ĭynamically to transient groups. , while transient addresses may be allocated Permanent multicast addresses areĪllocated by the Internet Assigned Number Authority That stands for a group of hosts, and may be either , while Class E addresses are reserved forĪ multicast (Class D) address is a 28-bit logical address Class D addresses are used for IP multicasting There are now five classes of IP addresses: Class A throughĬlass E. Thoughts on this one? And any thoughts on a good source to cite? A computer with a working NIC should be able to ping itself regardless of if it is plugged in or not, so connecting a cable wouldn't help in this situation. Likewise, the subnet would not effect the DHCP settings. The subnet wouldn't factor in, as the localhost address isn't affected by external network settings. Being unable to ping this address can be a symptom of a faulty NIC. 127.0.0.1 is the address for localhost and is used for testing purposes.The computer needs a static address set in DHCP.If a computer can't ping 127.0.0.1, what is the most likely reason?.So I am turning to the experts on this one. This question is in the Daily Challenge and, while it has a pretty decent success rate (79% currently), there is some discussion on how accurate the answer is and it seems like it's just the least worst instead of the best answer.

127.0 0.1 loopback