First off ping
and nslookup
are two totally and very different things:
ping
is sending an ICMP packet to the specified host directlynslookup
is querying a DNS server for the IP address of a hostname
If the host is down (for example), ping will fail. However, if you do an nslookup
it will still return the IP address of the host you're querying. Remember, DNS is essentially an address book - it translates or maps names to numbers.
Why does your ping
fail?
There are any number of reasons, but these are the "big three:"
- host can be down
- it can be configured to not respond to
ping
- the firewall can block/reject ICMP packets - from either/or both your computer, your network; their computer, their network
When I am on another machine on the same network, I can ping deeznuts.noodleofdeath.com successfully
If others can ping it, the host is obviously up and not rejecting packets. To find out why packets on a particular machine is being dropped, you need to do a packet capture with something like Wireshark to see where the packet is going and where it's failing.
I would look at these factors (in this order):
- firewall on the local machine that could be dropping packets
- network firewall (local network) blocking ICMP/ping packets from a particular host, range of addresses, subnetworkssubnets, or networks
- firewall on the remote machine blocking/dropping packets from particular hosts
- network firewall on the remote network blcokingblocking/dropping packets from a particular host, range, or subnet.
If others canAn easy test to see if it's related to something security like the firewall or IPS software is to assign the IP of the machine that can't ping to a different machine. If it fails, it's security related. If it works, theit's your host is obviously up and not rejecting packets. To find
I can't rule out why packetsany IDS/IPS software that may be running on the remote. For instance, if a host or firewall sees too many pings from a particular machine is being droppednode, you needit will stop responding to dorequests from that node. This is a packet capture with something likevery common tactic in preventing Wireshark to see where the packet is going and where it's failingDDoS attacks.