nmap -sS SYN-SCAN does not find all open Ports?

[bwagrocki () ficom de]

Hello,

I just used nmap to scan all open Ports on my Watchguard X Firewall. When I use -sT nmap finds all open Ports.When I 
use -sS nmap does not find some Ports (HTTP-80 and HTTPS-443).

Could anybody please explain to me, why nmap can not find those open ports?

Best Regards
 -Benjamin Wagrocki-

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