Shodan shows open ports but nmap says they are closed. any idea why?

Question

SMB port is open when I try to scan the host with shodan, but when I do it with nmap or any other scanner it says that the port is closed or filtered. any explanation? I tried all the basic firewall evasion techniques with nmap but none of them worked.

Shodan Scan Result:

Hostnames: xxxxxxxxxxxxxx

Number of open ports: 6

Ports:

22/tcp OpenSSH (6.6.1p1 Ubuntu-2ubuntu2.8)

80/tcp nginx (1.4.6)

137/udp

445/tcp Samba (4.3.11-Ubuntu)

8080/tcp Apache Tomcat/Coyote JSP engine (1.1)

8081/tcp

NMAP Scan Result:

Host is up.

PORT STATE SERVICE VERSION

445/tcp filtered microsoft-ds

Answer 1

Shodan is an archive of scan results. The system in question (there is only one on Shodan which matches this output) was scanned on July 9, and may have been taken down, had its IP changed, or been reconfigured since then.