On 10/19/2006 06:40 AM, L.V.Gandhi wrote:
On 10/19/06, Mumia W.. <paduille.4060.mumia.w@earthlink.net> wrote:On 10/19/2006 12:39 AM, cothrige wrote: > * John Hasler (jhasler@debian.org) wrote: >> The name is misleading. Ipmasq configures both NAT and firewalling. The >> default configuration is suitable for most, but you can tweak the scripts >> to do whatever you need. >> >> However, it is not clear that you need a firewall at all. If you have only >> the one machine, just don't open any ports. > > I guess I have never really thought about it that way. I have just > assumed that I was better off for having something like a firewall in > place on any computer connected to the internet. And I have opened no > ports intentionally, but now I am wondering just how to find out what > ports are open and how they got that way? Any recommendations? > > Patrick > > This site, http://www.grc.com , has a service called Shields-Up that will help you find out what, if any, ports are open on your computer.Also, "netstat -putl" will let you find out what listening ports are open.In my machine, following is the output. can you explain the significance of [the] columns? How to interpret it?root@lvghomepc:~# netstat -putl Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 localhost.localdo:mysql *:* LISTEN 4303/mysqld tcp 0 0 *:34637 *:* LISTEN 4539/rpc.statd tcp 0 0 *:sunrpc *:* LISTEN 3932/portmap tcp 0 0 *:auth *:* LISTEN 4485/inetd tcp 0 0 localhost.localdom:smtp *:* LISTEN 4475/exim4 tcp6 0 0 *:ssh *:* LISTEN 4514/sshd udp 0 0 *:32769 *:* 4539/rpc.statd udp 0 0 *:899 *:* 4539/rpc.statd udp 0 0 *:bootpc *:* 3913/dhclient udp 0 0 *:sunrpc *:* 3932/portmap
(Re-directed to the list.)Read "man netstat" to get the documentation on netstat. Reveal the port numbers using "netstat -putln"
You should go to http://www.grc.com/ and use the Shields-Up service. There they talk about the port numbers and their meanings.
On your machine, mysql is listening on tcp port 3306. RPC (Remote Procedure Call) is listening on tcp port 34637 and udp ports 32769, 899 and 111. Sshd is listening on tcp port 22, and exim4 is listening on tcp port 25.
Take a look at the GRC site. -- paduille.4060.mumia.w@earthlink.net