How can I open port?

your_shadow03 · 10-01-2009, 09:55 PM

I ran nmap on my fedora 9 system as:

Code:

[root@Innova ~]# nmap -vv localhost

Starting Nmap 4.53 ( http://insecure.org ) at 2009-10-02 08:04 IST
Initiating SYN Stealth Scan at 08:04
Scanning localhost.localdomain (127.0.0.1) [1714 ports]
Discovered open port 80/tcp on 127.0.0.1
Discovered open port 443/tcp on 127.0.0.1
Discovered open port 22/tcp on 127.0.0.1
Discovered open port 8080/tcp on 127.0.0.1
Discovered open port 139/tcp on 127.0.0.1
Discovered open port 111/tcp on 127.0.0.1
Discovered open port 2049/tcp on 127.0.0.1
Discovered open port 445/tcp on 127.0.0.1
Discovered open port 977/tcp on 127.0.0.1
Discovered open port 8009/tcp on 127.0.0.1
Discovered open port 631/tcp on 127.0.0.1
Discovered open port 3306/tcp on 127.0.0.1
Completed SYN Stealth Scan at 08:04, 0.08s elapsed (1714 total ports)
Host localhost.localdomain (127.0.0.1) appears to be up ... good.
Interesting ports on localhost.localdomain (127.0.0.1):
Not shown: 1702 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
111/tcp  open  rpcbind
139/tcp  open  netbios-ssn
443/tcp  open  https
445/tcp  open  microsoft-ds
631/tcp  open  ipp
977/tcp  open  unknown
2049/tcp open  nfs
3306/tcp open  mysql
8009/tcp open  ajp13
8080/tcp open  http-proxy

Read data files from: /usr/share/nmap
Nmap done: 1 IP address (1 host up) scanned in 0.157 seconds
           Raw packets sent: 1714 (75.416KB) | Rcvd: 3440 (144.504KB)

I want to configure sendmail and so do I need to open port 25.
Any idea how can I open that port?

Vhann · 10-01-2009, 10:54 PM

You do not need to open a port per say.

An open port means there is an application currently listening on the port. The fact that you don't see it opened means no application is currently using that port (which is fine since you _intend_ to use it).

Basically, just starting sendmail will actually 'open' the port.

Note though that you may need to configure your router/firewall or such in order for it to forward traffic on the given port (though this is highly improbable on port numbers under 1024).

Hope this helps, don't hesitate if you have further questions.

Regards,
Vhann

chrism01 · 10-01-2009, 11:01 PM

Actually, that's only true if you turn off the firewall.

service iptables stop

If iptables is running, then (assuming its a sane setup) you will need to open port 25 in the firewall (iptables) as well.

See section 27.1.16 http://www.linuxtopia.org/online_boo...onfig-iptables

your_shadow03 · 10-01-2009, 11:02 PM

Sendmail is running and still it shows "25" not open.

Vhann · 10-01-2009, 11:06 PM

Quote:

Originally Posted by your_shadow03

Sendmail is running and still it shows "25" not open.

Try following chrism01's advice by turning off iptables (I wasn't aware iptables blocked port 25)

chrism01 · 10-01-2009, 11:10 PM

That's what I meant by a sane setup; by default all ports are closed unless explicitly set open. See my link.

BTW, default (again security issue) for sendmail's cfg is to only listen on 127.0.0.1 ie localhost.
You have to fixup the cfg file and restart sendmail.

Modify /etc/mail/sendmail.mc to listen on all interfaces

dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl

Restart sendmail

your_shadow03 · 10-01-2009, 11:18 PM

Firewall is stopped.
The Entry is modified.