topic Response from nonexistent IPs in Network Security https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894728#M438149 <P>Good afternoon!</P><P></P><P>At my work I'm having an interesting issue.&nbsp; I am trying to map out ip space in certain areas of my network through firewalls and determine what IPs are active and not.&nbsp; The issue I am running into is that when I run NMAP or just a regular ping sweep I get a response no matter if there is a device on that IP or not.</P><P></P><P>Any ideas as to why this is?&nbsp; Is there a config in the firewall that could cause the firewall to respond to any port or ICMP sweep and act as the nonexistent device?</P><P></P><P>Thanks!</P><P></P><P>Jay</P> Mon, 11 Mar 2019 22:57:16 GMT galloway13 2019-03-11T22:57:16Z Response from nonexistent IPs https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894728#M438149 <P>Good afternoon!</P><P></P><P>At my work I'm having an interesting issue.&nbsp; I am trying to map out ip space in certain areas of my network through firewalls and determine what IPs are active and not.&nbsp; The issue I am running into is that when I run NMAP or just a regular ping sweep I get a response no matter if there is a device on that IP or not.</P><P></P><P>Any ideas as to why this is?&nbsp; Is there a config in the firewall that could cause the firewall to respond to any port or ICMP sweep and act as the nonexistent device?</P><P></P><P>Thanks!</P><P></P><P>Jay</P> Mon, 11 Mar 2019 22:57:16 GMT https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894728#M438149 galloway13 2019-03-11T22:57:16Z Response from nonexistent IPs https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894729#M438150 <HTML><HEAD></HEAD><BODY><P>If the firewall has a static NAT rule it will respond to a ping on behalf of the true device IP.</P></BODY></HTML> Tue, 24 Apr 2012 00:54:13 GMT https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894729#M438150 Marvin Rhoads 2012-04-24T00:54:13Z Response from nonexistent IPs https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894730#M438151 <HTML><HEAD></HEAD><BODY><P>There are no static NAT rules currently in the device. </P></BODY></HTML> Wed, 25 Apr 2012 13:49:15 GMT https://community.cisco.com/t5/network-security/response-from-nonexistent-ips/m-p/1894730#M438151 galloway13 2012-04-25T13:49:15Z