?
Solved

Opening ports

Posted on 2001-06-13
5
Medium Priority
?
197 Views
Last Modified: 2013-11-15
I am a newbie, just installed redhat 7.1, with the high security level.

Of course, now, I can't seem to telnet to it (although I can locally on 127.0.0.1) or web browse it (I'm sure I installed the http server, how do I check?!)

Is there a config file somewhere, or something I need to change to open up ports?
0
Comment
Question by:jezzar
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 17

Expert Comment

by:psimation
ID: 6185285
7.1 uses xinetd.
Very easy way to get telnet up ( if installed)
Type setup at the prompt, go to system services, make a tick infront of telnet (and one infront of httpd)
If you can't see telnet or httpd in the list, they are not installed.

Now, even if telnet is there and ticked, you must still make sure that it is enabled.
Go to /etc/xinetd.d edit the telnet file in that folder and make sure it reads disable, = no
Yet, If you place this machine on the net or large network, telnet is a bad idea, rather use SSH instead...

0
 
LVL 5

Accepted Solution

by:
vsamtani earned 200 total points
ID: 6185329
You need to look at some files in the /etc directory.

/etc/hosts.deny lists names and ip addresses of hosts that are not allowed access to the machine. If it's empty, then everything is allowed access. You should have a line here that says

ALL:ALL

which means "deny access to all services from all ip addresses" (unless allowed in /etc/hosts.allow)

/etc/hosts.allow lists names and ip addresses of machines that are allowed to access services. So you could have a line in there like this:

in.telnetd: <your telnet client ip address>

which would allow access to the telnet service from the specified address. Everything else would remain banned thanks to the /etc/hosts.deny file.

You also need to examine the files in /etc/xinetd. Xinetd controls access to a number of daemons, such as telnet and ftp and pop3. Each file in this directory controls a particular service. Have a look at the telnet file, and you'll see that it has a line

disable = <either yes or no>

Obviously, if it's disable=yes, then there will be no telnet access. It probably is on disable=no, since you can telnet to localhost successfully.

You should read the manual pages for hosts.allow and hosts.deny (type man hosts.allow). Also be aware that by default, root can never telnet in to a redhat machine. Read the man pages for login and securetty to find out why. If you want to be able to login as root from a remote host over an insecure network such as the internet, you should set up ssh (secure shell).

Vijay




0
 

Author Comment

by:jezzar
ID: 6185332
I have now enabled it in the setup, allowed it through the firewall settings, and checked the disabled=no but it still won't accept connections?! Is there a start command or anything?
0
 

Author Comment

by:jezzar
ID: 6185397
Thanks - did all the above, but nothing took effect until I rebooted! (Hey, is this windows or what?!) ;o)
0
 
LVL 5

Expert Comment

by:vsamtani
ID: 6185470
Rebooting probably wasn't necessary - what rebooting would have done is restarted the xinetd service. In Redhat, you can usually restart a service by typing:

/etc/rc.d/init.d/<name of service> restart

so in this case

/etc/rc.d/init.d/xinetd restart

Should have explained that - sorry :(

Vijay
0

Featured Post

Certified OpenStack Administrator Course

We just refreshed our COA course based on the Newton exam.  With 14 labs, this course goes over the different OpenStack services that are part of the certification: Dashboard, Identity Service, Image Service, Networking, Compute, Object Storage, Block Storage, and Orchestration.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Google Drive is extremely cheap offsite storage, and it's even possible to get extra storage for free for two years.  You can use the free account 15GB, and if you have an Android device..when you install Google Drive for the first time it will give…
This post contains step-by-step instructions for setting up alerting in Percona Monitoring and Management (PMM) using Grafana.
This video Micro Tutorial shows how to password-protect PDF files with free software. Many software products can do this, such as Adobe Acrobat (but not Adobe Reader), Nuance PaperPort, and Nuance Power PDF, but they are not free products. This vide…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
Suggested Courses

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question