Media for Nmap questions concering my router

Nmap questions concering my router

Hello i have a Speedtouch 530 modem/router. i use WinXP(Gentoo too :-)

when i namp from console i get this:

D:\nmap>nmap -sT -sV -O -P0 dslcustomer-225-52.vivodi.gr

PORT STATE SERVICE VERSION

21/tcp open ftp Alcatel Speedtouch aDSL router ftpd 23/tcp open telnet SpeedTouch DSL router admin interface 137/tcp closed netbios-ns 138/tcp closed netbios-dgm 139/tcp closed netbios-ssn 445/tcp closed microsoft-ds 1723/tcp open pptp? Too many fingerprints match this host to give specific OS details

Well i port scan my friend computer which he uses the same isp and same exact router i dotn see the same results:

D:\nmap>nmap -sT -sV -O -P0 dslcustomer-222-75.vivodi.gr

(The 1659 ports scanned but not shown below are in state: filtered) PORT STATE SERVICE VERSION

137/tcp closed netbios-ns 138/tcp closed netbios-dgm 139/tcp closed netbios-ssn 445/tcp closed microsoft-ds Too many fingerprints match this host to give specific OS details

Nmap finished: 1 IP address (1 host up) scanned in 281.141 seconds

a) why to me it reports i have 21, 23 and 1723 port open? i didnt open them btw. ISP did this? Is this because my ISP wants to remote managing me? For example to upload his own firmware? Why 3 ports and whats he is doing with every 3 of them?

b) Why doesnt report the smae from my friends pc when i nmap him? Is this because iam issuing the command behind my router, but if so whats the problem with that?

c) why the netbios ports are displayed if they are closed? other ports as closed as well but nmap doesnt display them. why for netbios it does?

d) I am also running an http server Apache v2.0.55 (win32) and a smpt server and have 4899 port open but it doesnt show up why?

e) Is nmap a really good port scanner or there is soemthign better?

Thank you.