This is a gotcha but be aware sometimes iptables may be active and loaded by default.
Also make sure you don't just disable firewalld but also stop it otherwise it will still block stuff:
systemctl stop firewalld
If the above is not the issue then it is possible iptables is running and blocking stuff too, so you'll need to stop iptables.
So in addition to opening firewalld or disabling it, you would need to disable iptables........
yum install iptables-services
systemctl enable iptables
service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]........
Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery.
To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl".
Install the utilities to make our bridge
sudo apt-get install........
So say you are behind a typical NAT/LAN setup whether at home, work or while travelling. What if you have a computer or server that you need to connect to from the outside?
Yes you could use a VPN but a quick and dirty, temporary and secure way is to use SSH's Reverse Tunneling Proxy feature.
On the remote ssh server host you need the GatewayPorts option enabled in sshd_config (be........
Whether you are at work, at the coffee shop or on the public internet here are some basic but effective rules for iptables that lock things down (eg. no one can SMB or SSH to you or really anything):
# Generated by iptables-save v1.4.21 on Fri Dec 14 14:00:08 2018
:PREROUTING ACCEPT [160:19844]
:INPUT ACCEPT [4:357]
:OUTPUT ACCEPT [2955:182236]
:POSTROUTING ACCEPT [2955:182236]
# Completed on Fri Dec 14........
systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
list-units [PATTERN...] List loaded units
By default Samba SMB/NMB listen on ANY and ALLIPs on your system by binding to 0.0.0.0. Obviously this is a huge security risk if you have a public facing server with both internal and external access. Usually when a system administrator sets up a samba server their intention is just to share with a LAN.
To do this you need to the following options under the [global] section in smb.conf
bind interfaces only = yes
interfaces = 192........
Check for crap in /var/lib/mysql like this
ls -al /var/lib/mysql/
drwxr-xr-x 24 mysql mysql 4096 Oct 3 18:30 .
drwxr-xr-x 20 root root 4096 Oct 3 04:23 ..
-rw-rw-rw- 1 mysql mysql 11776 Oct 3 17:10 c:exp.exe
-rw-rw-rw- 1 mysql mysql 48128 Oct 3 17:10 c:exp1.exe........
*Update so this doesn't work it must be something to do with the path of nfs or something else but the installer fails with "Installer crashed" at the end whereas with the CD/USB it works.
This assumes you've already installed and configured a separate PXE/DHCP server somewhere else and your /tftpboot directory is setup.
This is for Linux Mint 18.1 but generally applies to most versions although you may have tro change things like "casper"........
Change Host="192.168.5.99" with the remote IP allowed(this is of course more secure but also cumbersome if your IP changes). You could also have a single layer of protection that specifies the IP via firewall or both (of course both are far mor secure).
UPDATE user SET Host="192.168.5.99" where Host="localhost"
or for any/wildcard
UPDATE user SET Host="%" where Host="localhost&qu........
In Firefox I cannot connect to any website, proxy is disabled and outside network access is confirmed, no system or manual proxy was set on this Linux Mint/Ubuntu system. Normally this can be caused by proxy or DNS problems and the weird thing is that traceroute and ping to other IPs worked fine but even connecting to sites by IP was not working.
The connection was reset
The connection to the server was reset while the page was loading.........
service iptables start
iptables: Applying firewall rules: iptables-restore: line 40 failed
Say if you need to make a firewall script to block certain ports this works great.
for ports in 21 25 443; do
iptables rules here
I keep getting messages like this shortly after using the proxy (it works for a few seconds/page loads and then stops):
channel 12: open failed: administratively prohibited: open failed
I'm not sure what the issue is unless there's some kind of hardware firewall on the other end. I've used this exact configuration on multiple servers with no issue and even disabled iptables etc..........
genuine.com/IN: loading master file genuine.com.zone: file not found
_default/genuine.com/IN: file not found
I always found it silly that no one really talks about this and apparently many like me and even control panels like Plesk were still using hard paths. I always thought "why can't I just specify the name of the zone file and have bind find it". Surely the default search path must be /var/named or somewhere else but there is no such thing.........
I've only used it on Centos, soI thought I'd make a quick Debian guide:
Install the DRBD Package
apt-get install drbd8-utils
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
Use 'apt-get autoremove' to remove them.
This has stumped me a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic,I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work. So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first!
Both Nodes Say the Following:
version: 8.3.8 (api:88/prot........
One note is to secure MySQL, I don't know for sure but I believe you could login to MySQL remotely with no password during this operation (I'm not sure, maybe it doesn't accept blank passwords but I firewall MySQL port anyway and recommend you do the same).
First edit /etc/my.cf
Under the [mysqld] field add the following line somewhere:
Now restart mysql: service mysql restart or on Debian sty........
Trouble connecting between Windows XP and Windows 98 SharesOk a few things to check for:
* Disable all firewalls
* Make sure NetBEUI is enabled on both computers
* Make sure the Windows XP computer has the name of the computer logged in user of Windows 98 added as an XP user
* Add the XP user to anything you want to share
That fixed my problem........
Helpful IPFW ExamplesSomeone's real life examples:
Or you can try the FreeBSD Handbook guide:
Proftp Passive PortsIf you use a locked down firewall you can edit proftpd.conf and tell it something like this:
[quote:8419cab1f8]PassivePorts 6170 6270[/quote:8419cab1f8]
That would force all passive ftp traffic to ports 6170 6270 which you could then open on your firewall rather than leaving open ports 1024-65000 open........
Basic Port ListingHopefully someone finds this useful or at least interesting.
Name Port Protocol Description
Small services ........
In those 4 simple commands you can setup mutual key exchange between two sshservers by using a single login shell session and single window.
*Just change the IP address examples of (10.10.0.2) to the target of your mutual key exchange. It doesn't matter if the server is on a LANor WAN(well unless the server is behind a firewall and you cannot SSHinto it).........
This is something that annoys a lot of people, fortunately the Redhat style OS's are the most simple in this respect. I disagree that Debian's way makes sense, it is more of a hackish approach in how they implement iptables.
Anyway, for those who are using Redhat/Centos style OS's it is very simple.
Set your rules from the shell/command prompt and to save the iptables firewall rules so they are remember/loaded on boot just run this command: