I have been struggling with this for a very long time now. I have installed Fedora Core 9 on my computer. I have set it up as a caching-nameserver and this is working.
Then I wanted to secure my server with iptables, and I have so far made this script:
# Load the connection tracker kernel module
modprobe ip_conntrack
iptables -F
iptables -P INPUT DROP
iptables -P FORWARD DROP
[Code]....
I can reach the dns server with ping. When trying Nslookup it says that it got SERVFAIL from 127.0.0.1 trying next server, and then it times out.
When I use system-config-firewall, it asks what interfaces to trust. Where does it store that information for iptables (or whatever uses that info)? How iptables knows at what interfaces to use the rules?There is not that kind of information in /etc/sysconf/iptables and iptables-config.
i've got a few questions about iptables. i know how to set up ip tables to only allow from an ip address or a subnetting ip addresses. question is how do i allow from 2 different networks? would i need to create 2 lines of entry in iptables to the same port? e: allow 10.168.1.1 and 196.168.1.1 on port 22 is there a way to put all that in 1 line or would i need to create to rules for the port? i know i can use the ssh allow or deny but i'd like to stop access even before it gets to the ssh. stop it at the source kinda thing.
Wondering if anyone knows what the range specification is meant to do for the colonHAIN at the top of the iptables file? e.g. what is the 1:76 range mean for :OUTPUT ACCEPT [1:76] ?
# Generated by iptables-save v1.4.1.1 on Sat Dec 19 12:28:00 2009 *filter :INPUT ACCEPT [0:0]
I don't have a shell on FC12 with me to show the output of iptables -L -n but it looks good after above 2 commands. However, after issuing the following third command iptables -L -n gives "wrong" result
Namely iptables -L -n gives extra "/0" after 127.0.0.1 in the output I have checked on Ubuntu 9.10 and centos 5.4 and they don't give extra "/0"; iptables is not supposed to do that. Of course, I didn't invent these examples but they are abstracted from actual real life scenerio of trying to build rules on our servers.
i was hoping that someone in here could possibly help me out with my iptables rule set. First here is what i would like iptables to do, i want iptables to deny all packets or traffic from the outside coming in and for output allow the things i need like web and irc etc... Also, i would like iptables to deny access to all services like sendmail and ssh except i would like localhost to have access to everything. What i mean by localhost is that when i run my iptables script it loads fine except when i try ssh from localhost i get this output:ssh -l user localhostssh_exchange_identification: Connection closed by remote hostI know what most of you are thinking, why do i need to ssh into localhost from localhost just open another terminal, well i am getting myself familiar with iptables i want all services logged and blocked but not from localhost. I cant seem to figure out this problem and i have tried several different things. Here is my iptables script, I am hoping that someone out there can tell me what i am doing wrong...
#!/bin/bash iptables -v -F; iptables -v -A INPUT -i lo -j ACCEPT;
i am learning security and firewalling. i want to know . where a linux firewall is sufficeint and where it is not sufficeint? if you can explain why or give a reference i will be glad. is that security or traffic handling problem? when i should select a cisco product? in tarms of traffic and sceutiry. do you have any good alternative recomendation to Cisco
I am using squid on my fedora box as a proxy server.By default the iptables (Firewall) service is on.To allow web pages to my client machines i stop the iptable service.
#service iptables stop
By doing it client computers start browsing.kindly how can I add a rule so that without stoping firewall client compter work fine.my perver IP address is 10.1.80.10
I've got two routers, 10.0.0.0/23 and 192.168.2.0/24, which are joined by a Linux box with interfaces eth0 (10.0.0.2) and ra0 (192.168.2.2). I've got masquerading for ra0, and a route to 192.168.2.0/24 on 10.0.0.0's router. I CAN ping hosts on 192.168.2.0 from 10.0.0.0 just fine, but I CANNOT access web pages.Strangely, If I enable masquerading on eth0, and add a route to 192.168.2.0s router to 10.0.0.0, I can ping AND access web pages from 192.168.2.0Here is my current iptables
I use iptables firewall (v1.4.1) installed on FC8. I'm trying to limit the inflow traffic for the port 1723 to certain MAC addresses. To experiment with the mac option, I've written the following iptables rule:
Quote:
iptables -A INPUT -m -mac --mac-source 10:08:08:08:08:10 -j ACCEPT
It didn't work. It gave me this error message:
Quote:
iptables v1.4.1: Couldn't load match `-mac':/usr/local/libexec/xtables/libipt_-mac.so: cannot open shared object file: No such file or directory
Try `iptables -h' or 'iptables --help' for more information. Does that mean the mac module wasn't installed/enabled?
I am unable to restore my iptables from iptables-save after upgrading Fedora. I cannot get iptables-restore to work, and I have resorted to entering rules manually using the GUI.
I am using Fedora on my desktop pc. I want to know how can i protact my PC from outside world. What firewall policy should i implement in iptables to keep it more secure.
i set up a dmz to have a internet web server and ftp server, and ssh only from local network, so i wrote a iptables script to load during boot :
[Code]...
The problem is that everything works fine ( i have the same rules for other services such as samba, nfs, mysql on another server) BUT ftp there is no way to make it work. not even locally.when i try to connect, i log in, but while listing the directory i get MLSD ... and it hangs like this for a moment, then i get error message "connection time out" , "impossible to list directory". if i turn off the iptables script no problem,ftp works fine.. but why all services work and ftp no?
how do i have to modify the rules? what is strange also is that if i set as OUTPUT policy "accept", the server seems to be offline."host unknown" error message. I was thinking the rule INPUT is fine cause at least i can login, but the dir list is not going out, so gotta modify output rules. or state?
I've started a new job and have inherited a couple of RHEL4 64-bit servers. The firewall on them is currently disabled. I'm struggling to get them up and running as iptables is not the most user-friendly application. This lead me to downloading and trying a GUI front-end: Guarddog. Great app! But it doesn't have the default behavior I'm looking for. Here is what I need:
Default behavior: Firewall should be wide open, allowing ALL ports/IP's/TCP/UDP in and out of the server. Blacklist: Oracle TCP port 1521 needs to be blocked in/out of the server.
This will help get us passed our company's security vulnerability scan. (We aren't able to patch/upgrade Oracle at this time because we'd lose vedor support with a legacy app). I will use these settings as a starting point, and then once I learn more and get more comfortable with iptables (or a GUI app) then I can fine tune things to make them more secure. As far as I know (correct me if I'm wrong) once I get a script I just copy it into /etc/rc.firewall and it will load when iptables starts.
eth1 has connection to the net via gateway ..eth0 on the same machine has users on a intranet and needs access to the internet, i need to allow internet connection and prevent packets which logically originate from the internet getting into the intranet
Installing a router, and I need to completely "wipe" iptables (flush I mean) on both computers, and I think I run ufw/gufw on both, so that would need to be uninstalled. The router is very secure, has NAT, etc, etc, and I'd rather setup all that side of things in one point, rather than on each computer.
I new in Linux, I have a Centos5 since sunday and well I have to configure the iptables security of this cpu, I read a lot of examples of iptables in the internet and also another Thread from here but Really a don't know what to do, I saw lots of codes but first of all I don't know where I have to write that and my teacher don't want to help me in this homework. I tried to write the codes in applications --> accessories --> Terminal
After discovering that the firewall was wide open I decided to finally study the iptables docs and learn how to add rules. Now, I've not yet finished reading guides and documentation but I'd like some advice before I set the default policy on the input chain to deny. I have added a permissive rule for the loopback adapter so that programs that use it do not become mute suddenly. I will also use netstat to see what ports to open for each program that connects to the internet. I'm not that interested in what ports to open but how to find what ports to open.
