Visit Our UNIX and Linux User Community


closing open ports


 
Thread Tools Search this Thread
Special Forums Cybersecurity closing open ports
# 8  
Old 09-27-2001
One last thing----

Just one last little bit, your inetd.conf file is a better reference for what is running on the box, under inetd,(not to mention the use of lsof and looking at /etc/services) than an nmap scan. nmap is guessing at what is running on what port from a list of what is assumed to be a known service on those ports, usually anything above port 1024 (and sometimes, below it) is arbitrarily set to serve from that port. BackOrifice and NetBus could be config'd to run from other ports, so can netcat and other such tools. Your best bet is stripping down to only what you need, and keeping a sharp eye out for any new servers being put out there. You can use lsof to get an idea (okay, see what's happening) of exactly what proc is using which port so you can see who is serving what out of your box.
The nmap scans are excellent for finding servers that are nto running under inetd's auspices. Sounds like you're going in the right direction....


Later,


loadc
# 9  
Old 09-27-2001
Ummmm...

I've never seen SIGUSR1 used for this.
It has always been SIGHUP.

The way to get inetd to re-read inetd.conf
is....

find the process id of inetd...

ps -ef | grep inetd

...then as root do...

kill -HUP process_id_of_inetd

... it apparently ignores the signal if it did
not come from root.

Are you sure Linux uses SIGUSR1?
# 10  
Old 09-27-2001
Computer

Absolutely Beautiful...

kill -HUP pid

worked like a charm...

new nmap scan of the external interface reports that ftp and telnet are toast..

thanks for the help...

Smilie
# 11  
Old 09-28-2001
For clarity sake, the SIGUSR1 kill spec is used for xinetd. Regular ol' inted, HUP (signal 1) should work.

Also, for lazy people like me, I usually just do this:
killall -1 inetd

It kills by name rather than trying to find the PID.

Previous Thread | Next Thread
Test Your Knowledge in Computers #277
Difficulty: Easy
Solaris is a version of UNIX System V Release 4 (SVR4), jointly developed by Sun and AT&T, and was licensed by Sun from DEC to replace SunOS.
True or False?

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Closing open file descriptors from /proc/pid/fd

Hi guys, i need to write a shell script that will close file descriptors from /proc/pid/fd will calling exec 4<&- solve the problem ? thanks in advance :) (15 Replies)
Discussion started by: alpha_romeo
15 Replies

2. IP Networking

Open/close of ports

Hi, I have read some forum theads about the open and close ports. some points are clear and it is not working on my machine or something am i missing? I have commented out a port /etc/services, one application uses then when i use the telnet <hostname> <port_blocked> it shows connected..... (1 Reply)
Discussion started by: balamv
1 Replies

3. UNIX for Dummies Questions & Answers

open ports and services

just a quick question: a. whats the simplest command to check open port and the corresponding services? example: bash-2.05# netstat -an | grep LISTEN *.199 *.* 0 0 49152 0 LISTEN *.8989 *.* 0 0 49152 ... (1 Reply)
Discussion started by: lhareigh890
1 Replies

4. Shell Programming and Scripting

closing unwanted open ports using scripts

i have a text file i.e file1.txt which shows open ports on particular system. i have another text file i.e file2.txt which shows a list of allowed ports on a system. for eg: file2.txt 22/tcp ssh 23/tcp telnet. can i have a script which would compare these text files ,file1 and file2 ... (1 Reply)
Discussion started by: anand121
1 Replies

5. Solaris

Open ports in solaris 10

hi guys, may i know the exact steps to open a port in solaris.i have some rough idea - which is adding the port number in /etc/services. but i am not sure the correct conventions, steps or any other steps. kindly advise.thanks guys ! (1 Reply)
Discussion started by: cromohawk
1 Replies

6. Solaris

open ports solaris 8

Hello, I have a number of Solaris 8 Sun servers that have open ports that I cannot identify. I see some with 1013-1023 (which are reserved ports according to the IANA. Lsof does not identify these. I rebooted the server and they went off, but this morning I saw they were all back on again. Any... (1 Reply)
Discussion started by: csgonan
1 Replies

7. Shell Programming and Scripting

Check open ports every ...

Hello, i need a script (bash type maybe?..), which would check open ports on 127.0.0.1 and then compare open ports with "registered/allowed" port list and try to kill the program who uses unregistered ports. It would be great that script would be started lets say every 5 or 10 minutes. You see i... (2 Replies)
Discussion started by: MorchiuS
2 Replies

8. IP Networking

Closing out ports???

Hi all Is there a command that I can use to close out open ports? I did a netstat - a -p and got a long list of ports open (see sample below). I have disabled the some of the applications from /etc/services/. But there are still applications listening on certain ports. I need to know how to... (6 Replies)
Discussion started by: skotapal
6 Replies

9. Cybersecurity

firewall vs. closing ports

This may be kind of a stupid question, but here goes: Say I'm running a FreeBSD webserver (w/apache). I've managed to close ALL open ports (including SSH/telnet and portmapper), excepting '80' that apache is listening on. A netstat -a shows me nothing open. Discounting DoS/DDoS or holes in... (7 Replies)
Discussion started by: adam_crosby
7 Replies

Featured Tech Videos