Ubuntu Security :: Use Address Not Ip In Iptables?
Jul 24, 2010i need to open this address ftp.nai.com, is there a way to use address not ip in iptables?
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Security :: Blocking An Ip Address Range Within Iptables?
Mar 30, 2009I am setting up a iptables firewall on one of our servers, and I would like to block a range of addresses from getting into the system. I am using a script that does a BLACKIN and BLACKOUT methodology for specific addresses. One example is the following:
Code:
$IPTABLES -A BLACKIN -s 202.109.114.147 -j DROP
...
$IPTABLES -A BLACKOUT -d 202.109.114.117 -j DROP
What would be the correct syntax to use if I wanted to block an entire remote subnet from getting into the server?
Security :: IPTABLES - Restrict Internet Access Based On Time Of Day And MAC Address
Feb 6, 2010I am trying to configure my Linux router to restrict Internet access for one computer on my LAN. It needs to be restrictive based on the time of day and the days of the week. I am using the MAC address of the computer to single out the one computer that needs to be blocked. However, this is my first attempt at making any rules with iptables, and I am not sure if I am doing this right. If some one can take a look at this I would greatly appreciate it. This is what I have done so far.
Here is my thinking. Create a new target. Check the MAC address, if it is NOT the offending computer return to the default chain. If it is the offending computer check that we are between the allowed hours and dates and ACCEPT. If we are not within the time/date range then drop the packet.
Code:
Here I am trying to route all packets regardless of the computer on the LAN into the blocked_access chain for checking.
Code:
Is it a good idea to route all traffic through the blocked_access chain? I do run other servers that are accessible from the Internet, so I am not sure how this setup will affect that. I also use shorewall on the router to setup iptables for me. How would I integrate this with shorewall?
I am using squid to block access when he is using the web browser. However, he is still able to play games(World of Warcraft) and the like.
I am using Debian sid, iptable(1.4.6), shorewall(4.4.6), kernel 2.6.32-trunk-686.
Security :: Address Space Randomization On 2.6.28-15-generic Ubuntu 9.04 - Finding Base Address?
Sep 14, 2009Im an academic (university networks and security lecturer) studying/teaching network and operating system security, and inspired by the work of Hovav Shacham set about testing ASLR on linux. Principley I did this by performing a brute force buffer overflow attack on Fedora 10 and Ubuntu 9. I did this by writting a little concurrent server daemon which accidently on purpose didnt do bounds checking.
I then wrote a client to send it a malicious string brute forcing guessed addresses which caused a return-to-libc to the function usleep with a parameter of 16m causing a delay of 16 seconds as laid out in [URL] Once I hit the delay I new I had found the function and could calculate delta_mmap allowing me to create a standard chained ret-to-libc attack. All of that works fine. However .... To complete my understanding I am trying establish where I can find the standard base address for ubuntu 9 (and other distros) for the following, taken from Shacham:-
Quote:
[code]....
/proc/uid/maps gives me some information but not the base address ldd also gives me the randomised starting address for sections in the user address space but neither gives me the base address. Intrestingly ... when a run ldd with aslr on for over (about) 100 times and checked the start point of libc I determined that the last 3 (least significant) hex digits were always 0's and the fist 4 (most significant) where between 0xB7D7 and 0xB7F9. To me this indicated that bits 22-31 were fixed and bits 12-21 were randomized with bits 11-0 fixed. Although even that doesnt define the boundaries observed correctly.
Note: I am replicating the attack to provide signatures to detect it using IDS, and for teaching purposes. I am NOT a hacker and if needed to could reply from my .ac.uk email address as verification.
Networking :: Add Ip Address In IPTables?
Nov 11, 2010How can I add ip address which is multiple of 3 and to 255? That is I want to block ip address which is coming from multiple of 3 to 255.
As an example 192.168.0.3,192.168.0.6,192.168.0.9,192.168.0.12 etc.
Ubuntu Security :: Is Posting The Hardware Address A Security Risk
Feb 28, 2011When posting results from ifconfig, it shows the hardware address of etho, etc. Would you consider that to be a security risk ?
View 9 Replies View RelatedUbuntu Networking :: Redirect Network Traffic To A New IP Address Using IPtables?
Jun 19, 2011how to redirect network traffic to a new IP address using IPtables. I am using Baffalo router and the rtos used is DD-WRT. Basically, I want it so that any connection going through my router to a specific IP (say, 192.168.11.5) will be redirected to another IP (say, 192.168.11.7) so any outgoing connections made by a program that is attempting to connect to192.168.11.5 will instead connect to 192.168.11.7.
View 2 Replies View RelatedGeneral :: Iptables Restrict Ssh Session By Mac Address?
May 24, 2011I'm in the process of restricting access to my Linux production box, where ssh access needs to be limited to only a few MAC addresses.I've followed the instructions outlined in this guide and ran the following two commands:
/sbin/iptables -A INPUT -m mac --mac-source XX:XX:XX:XX:XX:XX -j DROP
/sbin/iptables -A INPUT -p tcp --destination-port 22 -m mac --mac-source XX:XX:XX:XX:XX:XX -j ACCEPT
root@xxxx:~/#: iptables --list
[code]....
Networking :: Set Iptables To Forward All On An Aliased Ip Address?
Apr 15, 2009I have three machines on three networks192.x.x.x10.x.x.x172.x.x.xThe routers are set to forward communication between 192. network and 10. network, and between the 10. network and the 172. network.However, there's not routing between 192. and 172.I want to fix that by using a machine on the 10. network to forward communication between the other two networks.The machine has one etherent connection eth0 whose address is 10.1.1.11I set up an aliased ip address eth0:0 to be 10.1.1.12 using Quote:ifconfig eth0:0 10.1.1.12Then I tried to set forwarding rules the 10. machine such that 10.1.1.12 address will provide access to the machine 172.1.1.55 as followsQuote:# iptables -t nat -A PREROUTING -d 10.1.1.12 -j DNAT --to-destination 172.1.1.55The default policies for all chains is ACCEPT.I then try to access 10.1.1.12 from 192.1.1.20 expecting it to actually access 172.1.1.55 ; it does not work
View 3 Replies View RelatedGeneral :: Allow Access To Server From Only 1 IP Address Using Iptables?
Aug 3, 2011I have a server located remotely that I'd like to protect by allowing access to only my IP address (on any port). Currently anyone can access the server using ssh, http, and any other services that my server is running. (The reason I need to protect it for now is that it's a test/development server and really only needs to be accessed by me.)
The downside of doing this is every time my desktop IP address changes (from where I access the remote server), I would need to update the iptables configuration. (This could be a hassle, but based on my limited knowledge it seems to be the best way to allow access from only myself.)
Could anyone share how to allow access to my server using iptables from only my IP address and on any port?
Red Hat / Fedora :: Changing Outgoing DNS (port 53) IP Address With Iptables?
Mar 31, 2009I need to know what the Iptables "code" is to change the outgoing/Incoming IP for port 53 (DNS). I'm running CentOS on a dedicated server. I very familiar with Putty and SSH. So I don't need much details, I just can't figure this out. I asked my server providor but they deleted my ticket and didn't answer me.I tried this but am not sure if this correct of working?
View 5 Replies View RelatedNetworking :: Stop IPTables To Resolve Source Address?
Oct 25, 2010Here is a glimpse of my IPTABLES
http://pastebin.com/WvHAC46A
I see in the column of sources the addresses being resolved to domain names is there a way I can stop this?
Fedora X86/64bit :: Create A Script To Show The Last Time Iptables Had Seen A Given IP Address?
Jun 20, 2009i was trying to crate a script to show the last time iptables had seen a given IP address (contained in the ipt_recent kernel hook -- my user-defined table name is 'iplist'). The ipt_recent table yields the following information (IPv4 addresses masked for paranoid reasons):
Code:
src=www.xxx.yyy.zzz ttl: 114 last_seen: 9355600126 oldest_pkt: 1 9355600126
src=www.xxx.yyy.zzz ttl: 109 last_seen: 10020040763 oldest_pkt: 1 10020040763
src=www.xxx.yyy.zzz ttl: 111 last_seen: 8106864077 oldest_pkt: 3 8103790647, 8106530788, 8106864077
src=www.xxx.yyy.zzz ttl: 109 last_seen: 9937861664 oldest_pkt: 1 9937861664
src=www.xxx.yyy.zzz ttl: 115 last_seen: 8244867102 oldest_pkt: 1 8244867102
The attempted command used was:
Code:
cat /proc/net/ipt_recent/iplist | awk '{print ($1 ,system("date -d @" $5));}'
Such command yields the following (I'm willing to live with the trailing zero):
Code:
Wed Jun 20 05:48:46 EDT 2266
src=www.xxx.yyy.zzz 0
[code]....
I presume the ipt_recent table uses the standard UNIX epoch timestamp. Am I using the date command syntax incorrectly, is this a 32-bit vs 64-bit break, or it is something else? Please note that I am using FC10, and I have double-checked my system clock settings (both BIOS and OS). The system has only been running during 2009 (no reboot yet).
Ubuntu Security :: How To Reset The Iptables
Jan 14, 2010i ran this
Code:
iptables -N rate-limit
iptables -A rate-limit -p tcp -m conntrack --ctstate NEW -m limit --limit 3/min --limit-burst 3 -j RETURN
iptables -A rate-limit -j DROP
iptables -I INPUT 1 -p tcp --dport 22 -j rate-limit
i am no longer able to ssh in to the machine , how can i reset iptables and firestarted back to default?
Ubuntu Security :: Iptables Configured By UFW ?
Sep 17, 2010I've recently moved from Firestarter to UFW/GUFW, and I wonder if someone could confirm if my iptables configuration is secure.
When I enter sudo iptables -L i get:
Code:
Ubuntu Security :: Iptables Allow Via Spesific NIC?
Dec 29, 2010eth1 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
View 1 Replies View RelatedUbuntu Security :: How To Clear Iptables
Apr 21, 2011Installing 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.
View 2 Replies View RelatedUbuntu Security :: Both Ufw And Iptables Running Together?
May 23, 2011Can I have both ufw and iptables running together? My server is currently using ufw, if I add an iptables rule will it have any effect?
View 6 Replies View RelatedUbuntu Security :: Can't Access The Email - Iptables
Mar 12, 2010To get my Thunderbird email to work and to do FTP to my website I have to use TERMINAL and enter the following code in Root;
iptables -F
At one point weeks ago I got Gufw and I don't remember if that had any effect.
Ubuntu Security :: Iptables Is Not Automatically Displayed?
May 18, 2010I suspect this is one of these questions from Window users who see something different in Ubuntu.
My understanding is that the Ubuntu firewall (iptables) is always on. However, the GUI client (firestarter) shows this more obviously.
I suppose I am used to ZoneAlarm in XP where everything was displayed more obviously.
So, iptables in not automatically displayed, but is working, right?
Ubuntu Security :: Iptables - Script Is Not Working?
Jun 11, 2010see many threads / websites about how to configure iptables. They say if you use these
rules it will allow http traffic. But they don't work. I like to deny all then allow specific ports open for traffic.So far I tried the script to flush and update my iptables rules, trying to open port 80 and 53 for http and DNS traffic:(I made the script executable, with $ iptables -L -v I can see that the rules are changed after I run the script. )
Code:
#! /bin/bash
iptables -P INPUT DROP
[code]...
Ubuntu Security :: Configuring Iptables To Allow VNC And OpenVPN?
Jun 20, 2010I'm running Ubuntu 10.04 LTS as a VM in Hyper-V, and accessing it via VNC with a machine in the same broadcast domain. I'm using OpenVPN to connect to XeroBank. I have instructions for configuring iptables to permit establishing and using the XeroBank connection, while blocking all other traffic on eth0. I've followed them successfully. I need to also permit the VNC connection, and haven't managed that. FWIW, the VM is at 192.168.111.12::5900 and the workstation is 192.168.111.2.
The attachment to this post lists the recommended contents for each Shorewall file. Which files need changed, and what do I add to each?
Ubuntu Security :: Update Mcafee Behind Iptables?
Jul 29, 2010i opened access to [URL](without port limit) in iptables to let my systems to update mcafee, but still get unable to download in mcafee update log.
i have another ip that tried to connect via port 21 on those machines, but the ip is not belongs to [URL], is this possible thats redirecting?
Ubuntu Security :: Allow Internet Between Certain Hours Using Iptables?
Jan 6, 2011I typed this into the command line:sudo iptables -A INPUT -p tcp --dport 80 -m time --timestart 12:00:00 --timestop 23:59:59 --days Sat, Sun -j ACCEPTI get this error:iptables v1.4.4: unknown option '--days'How do I do something similar above in which I allow the internet to start at 12 o clock on Saturdays and Sundays
View 4 Replies View RelatedUbuntu Security :: Iptables Port 25 Is Open
Feb 28, 2011I've recently installed 10.10 server edition, and I must say it was a pleasant suprise, it's just the way I like it. I use it as a squeezebox-server. But I've run into a problem with the firewall. I did a portscan, which told me there are more ports open then I've told UFW to open. Among which port 25 and 119, when I telnet from another PC to those ports, the connection gets accepted, although there is no answer to any commands (as expected, there's no mail server running). Iptables print-outs also don't mention anything about the respective ports or a daemon that could be responsable, and the same applies to "ps -e" or "ps aux".
Iptables seems to be working, when I remove the rules to allow samba to work, I can't reach the shares, and when I insert them again I can reach the shares. "sudo ufw deny from any" as last rule doesn't change anything either (deny incoming is default (although I never issued the command "ufw status verbose" says it is) so it shouldn't, but ports 25 and 119 shouldn't be open either).
Ubuntu Security :: Iptables For Router/proxy?
Apr 1, 2011Rather than use pfsense, etc I decided to create my own router/proxy etc based on an atom base with 2 nics.Proxy/routing/dns/etc all working fine, I now though want to lockdown the fw rules.ETH1 is the WAN NICETH2 is the LAN NICI'm guessing i want to allow anything out of ETH1, but only allow incoming to ETH1 when its established or related... What about ETH2 though? Any ideas pls? Am used to configuring iptables on single nic, certainly not a router.
Code:
Chain INPUT (policy ACCEPT 18535 packets, 10M bytes)
pkts bytes target prot opt in out source destination
[code]....
Ubuntu Security :: Why These Packets Droped By Iptables
Apr 30, 2011i dont know why packets dropped? and something else what are those numbers for default policy in [] means?this is rules:
Code:
# Generated by iptables-save v1.4.4 on Sun May 1 00:09:57 2011
*mangle
[code]....
Ubuntu Security :: Installing And Setting The Iptables On U 8.04 LTS?
May 26, 2011can anyone advise the best practice of installing and setting the iptables on U 8.04 LTS? currently iptables is not installed nor as package nor included as kernel module.
View 2 Replies View RelatedUbuntu Security :: Iptables: MAC Filtering With A File?
Jul 2, 2011I'm wanting to use mac filtering to restrict access to certain machines. I already know that I can just add MACs line by line, but is there a way to specify a list of MACs? That way it would be much simpler to maintain a list of acceptable/unacceptable hosts.
I'm not going to rely only on this list because of spoofing, but it would be nice as another "layer" of protection.
Ubuntu Security :: Modify The Iptables Rules In Any Way?
Jul 9, 2011what do the following two commands do? Do they modify the iptables rules in any way?
sudo /sbin/iptables -L -n
sudo /sbin/ip6tables -L -n