Security :: Port Mapping On A Machine Using Iptables?
Jan 9, 2010
I want to do port mapping on a linux machine using iptables.I have a service listeneing on port 2000 udp and I want to add iptables rule, which will map incoming packets on port 2001 to port 2000, so that service will accept the connections.The idea is that I don't want to change the default port for the service, but to make internal port redirection from (2001 to 2000), so the default service port will be filtered by iptables, and the other port will be open to the outside. The internet host connects to the linux machine on port 2001. The linux machine change destiation port from 2001 to 2000 and the service (on the same machine) process the packets and accepts the connection.I tried adding the following to my iptables rules, but it didn't work out:
$IPTABLES -A FORWARD -p udp --destination-port 2001 -j ACCEPT
$IPTABLES -t nat -A PREROUTING -i eth0 -p udp --dport 2001 -j REDIRECT --to-port 2000
View 6 Replies
ADVERTISEMENT
Apr 18, 2011
Is there any way to verify if packets being trafficked over a certain port are valid for the service you want to use this port for?
One obvious example that probably clarifies my question:
When I open port 443 (outgoing or incoming) for https/ssl traffic, I don't want this port to be used for say openvpn traffic.
Thus: when someone wants to surf to a website with https, it should be ok but if someone wants to connect to his home openvpn server over that same port, it should be blocked.
View 5 Replies
View Related
Feb 28, 2011
I'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).
View 2 Replies
View Related
Dec 24, 2010
I'm trying to open port 119. I already have a few ports open. I've used webmin to open both incoming and outgoing ports. iptables --list --numeric gives me:
Code:
...
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:10000
[code]....
View 4 Replies
View Related
Sep 5, 2010
I've got two virtual machines running, the first VM (VM1) has two network interfaces, one bridged with my real lan, one a private subnet. The second VM (VM2) has one nic, only on the private subnet.
I have VM1 acting as a router for VM2, giving access to my real lan for internet access. The problem I'm having is I cannot get VM1 to forward ports 80 (http) or 222 (ssh) to VM2 from my real lan.
Here is the script I've cobbled together from various (foreshadowing!) locations:
Code:
View 1 Replies
View Related
May 24, 2011
I would like to allow incoming and outgoing connections when I'm connected to a wired connection, but drop it otherwise. I noticed that ufw can't block outgoing traffic because of will I give iptables a try. I'm unsure if dropping packages that are outgoing will work, the rule after the block rule will allow all outgoing connections.
This what the rules are intended to do, unsure if that is actually the case. Allow all loopback traffic. Allow ping replys Allow incoming on port 12345 if eth0, deny otherwise. Allow outgoing on port 12346 if eth0, deny otherwise.
Code:
iptables -A FORWARD -j DROP
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -p icmp --icmp-type 0 -s -m state --state ESTABLISHED,RELATED -j ACCEPT
[Code]....
View 3 Replies
View Related
Nov 9, 2009
I'm using iptables with modules ip_contrack_ftp to be able to use passive ftp. It works well as long as port 21 is being used as listening port. Is there any way to make it work when I configure my ftp server (vsftpd) to listen on an alternative port, lets say 21001 or something? The helper module only seems to be working properly with the standard port, so I was wondering whether there was a way to "tell it" that another port is being used? I mean, of course I make a rule in fw to allow traffic to the alternative port.
But once it's time to start passive connection, then the iptable module cannot handle it properly. I could solve the problem by making a range of passive ports in the ftp-server configuration and allow the incoming traffic to them, but then using helper modules doesn't make any sense. I just want to allow the traffic to the listening port and then want the ip_contrack_ftp module to take care of the rest. This is what I do today - but only port 21 seems to be working. Is there a way to do this with a non-standard ftp port?
View 5 Replies
View Related
May 16, 2011
I am currently running Debian 6. I would like to know if there is a way and how i would go about blocking a certain IP range from connecting to my server within a certain port range. Say for example.
i want to block ip range 123.123.123.* from connecting to my server on the ports 33000 - 43000. But, i want to allow them to connect on any other port range, and i want to be able to allow connections from my server to the blocked ip range on those same ports. so, blocking incoming only on the above port range.
using iptables.
View 1 Replies
View Related
Jan 11, 2011
I am at a loss how to prevent Denial of Service attacks to port 25 and not block legitimate connections from 2 Barracuda 800(s) and block smart phones such as iPhones/Blackberrys/iPhones that use the server smtp.server.com for email.
Presently for port 25
RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT
The 2 Barracuda 800(s) make port 25 connections all the time, plus users with smart_phones have the incoming server type:
IMAP
pop.server.com
smtp.server.com
Is there a way to keep Denial of Service attacks from happening with iptables rules without causing blocking to the Barracuda(s) that make constant port 25 connections & smart phones that poll? I was thinking if I allowed the Barracuda(s) in these lines
-s (barracuda)24.xx.xx.xx -d (emailserver)24.00.xx.xx -p tcp -m tcp --dport 25 -m state --state NEW -j ACCEPT
Where the source would be the Barracuda going to the email server. It would be allowed, then I am left with how to allow other connections like Smart_Phones that connect via Port 25. I am thinking if I put rules in place doing connection counts in a minute it would result in errors connecting to the server and people would start complaining. Plus any limiting may result in blocking real traffic. Then would I need to allow the ISP range in the above example to accept port 25, I am still left with how to drop a flood/denial of service attack.
View 4 Replies
View Related
Jan 3, 2011
how can i drop igmp port 0 packets with iptables rule? my log file is full of this router advertisement.
View 2 Replies
View Related
Jul 13, 2010
I am setting up tomcat server on my Centos 5.5 machine. I've been advised to run tomcat on 8080 as non root user and redirect traffic to it from port 80.
I searched and found the following iptables commands for this:# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT -to-ports 8080
# iptables -I INPUT -p tcp --dport 8080 -j ACCEPTI have a doubt:
Tomcat is not accessible via port 80 without the second command. But the second command opens 8080 and makes it accessible over the internet (tomcat is accesible via both: www.<website>.com and http://<ip address>:8080). This doesn't seem right. Is there some simple (iptables) way to redirect traffic "internally" from port 80 to 8080 without having to open 8080 to the internet.
View 3 Replies
View Related
Dec 23, 2010
I'm trying to limit access to port 8443 on our server to 2 specific IP addresses. For some reason, access is still being allowed even though I drop all packets that aren't from the named IP addresses. The default policy is ACCEPT on the INPUT chain and this is how we want to keep it for various reasons I wont get into here. Here's the output from iptables -vnL
[Code]...
Note the actual IP we are using is masked here with 123.123.123.123. Until I can get everything working properly, we're only allowing access from 1 IP instead of 2. We can add the other one once it all works right. I haven't worked with iptables very much. So I'm quite confused about why packets matching the DROP criteria are still being allowed.
View 10 Replies
View Related
Jun 6, 2011
I'm trying to open port 8080 on my application server. I've included it in my iptables; however I still cannot access through ssh nor putty and it doesn't show up when I netstat either.Here is my iptables-config:
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -s xxx.xx.x.0/24 -j ACCEPT
[code].....
View 7 Replies
View Related
Apr 4, 2011
I'm trying to use iptables in order to forward all the incoming packets for port 5555 to port 5556 on the same server (192.168.2.101).
I wrote the following commands:
iptables -A PREROUTING -t nat -i any -p tcp --dport 5555 -j DNAT --to 192.168.2.101:5556
iptables -A FORWARD -p tcp -m state --state NEW -d 192.168.2.101 --dport 5556 -j ACCEPT
View 3 Replies
View Related
Feb 20, 2010
I'm using a Debian servers, as router/firwall.. I've two ethernet interfaces into the server, one for wan and one for lan. The i use SNAT so my LAN clients can access the internet throgh the debian router. That is working... Now i want to be able to access servers on the LAN site from the WAN site, and i wanna use port address translation (PAT). I have a FTP server running on a lan server, so i'm trying to portward port 21.
iptables -t nat -A PREROUTING -p tcp -i eth1 -d (WANIP) --dport 21 -j DNAT --to 192.168.1.2:21
When people try to access my FTP from the WAN site, they are redirected to the local FTP server, and they are promted for crendentials, but when the credentials are typed, and the local ftp server should answer the wan request, the connections dies.
The wan clients are being promted for credentials, so they are redirected to the local lan server, but after that the connections dies, so i think there is some kind of nat problem, when the local lan server is trying to respond to the wan request..
Here i my iptables script:
#flush table
iptables -F
#input regler
[code]....
View 6 Replies
View Related
Aug 5, 2009
If I forward port 80 to port 3128 for squid with an iptable rule, does port 3128 have to be open on the firewall or is this all routed behind the firewall?
View 4 Replies
View Related
Mar 25, 2010
I have a mail server on which I would like to block port 25 on my eth0 for everyone except our external spam filter. the problem is that I want our users to be able to connect via port 10025 which is forwarded to port 25, which then is blocked...
View 2 Replies
View Related
Aug 7, 2009
Wondering if there is a uPNP Port Mapping Utility available for Fedora. Something like this :
[URL]
The program seems to be Mac only tho.
View 1 Replies
View Related
Apr 25, 2009
How can i redirect data received on a port to another port located in a different machine? Can i do this using IPTABLES ?
View 4 Replies
View Related
Jul 29, 2009
I successfully installed the virtual box on my fedora 8 system, and also created a virtual machine with windows xp OS, it works nicely, I try to configure the serial port of my virtual machine and try to configure the path for the port "screen shot are attached" it gives me the error message also the "screen shot are attached" for your review.Is kind of mistake is going on during the path setting, and how to set the path for configuring the serial port of my virtual machine so that I can use the hyper terminal tool of windows.
View 4 Replies
View Related
Feb 19, 2010
Posted in wrong section. Moved to Linux Servers Forum.
View 2 Replies
View Related
Nov 1, 2010
sudo ssh -L 750:192.168.123.103:873 username@192.168.123.103It does exactly what it's supposed to do, but how do i edit / remove this rule?Is there some config file where i can alter the forwarding? How does it get stored?Im using Ubuntu 10.10Server Edition (allthough i recon it would be pretty much the same across all versions
View 5 Replies
View Related
Apr 27, 2011
I'll explain this in one sentence: Is it possible to program a port-binding shellcode in which people across the Internet can connect to, without being thwarted by the router blocking their data because the port its bound to doesn't allow port-forwarding
View 2 Replies
View Related
Dec 19, 2010
When a user that has rsa public key set in ~/.ssh/authorized_keys file logs in via ssh an sshd process is started to handle the ssh session.Periodically we audit the authorized keys and remove them from the system and authorized_keys file. This means the next log in attempt will fail, which is fine.However we need to terminate current ssh sessions in progress that use the rsa key.I have not been able to determine a way to map sshd processes with authorized_keys entries.
View 11 Replies
View Related
Mar 18, 2011
iptables -A INPUT -p udp --dport -j ACCEPT
iptables -A INPUT -p tcp --dport -j ACCEPT
iptables -A FORWARD -p udp --dport -j ACCEPT
iptables -A FORWARD -p tcp --dport -j ACCEPT
and the rules are placed in iptables, i can see them when I do iptables -L. But when I do netstat -an | grep 161 I can see that port 161 (SNMP) is not listening. Why?
View 7 Replies
View Related
Jan 13, 2010
I am running a voip server on port 5060. I want to hide this to all the robots scanning the net permanently - I know this is not enough security - it is just to prevent them from wasting by bandwidth testing all usernames until fail2ban stops them !
I'd like to have port 5060 accepting requests only from 'trusted' hosts, while others (client with dynamic ip) use port 5065 - thus, port 5060 will only appear open for some trusted partners and the bots will skip to something else.
I have setup the iptables rules succesfully to accept only trusted hosts.
-A RH-Firewall-1-INPUT -s 93.x.y.z -p udp -m state --state NEW -m udp --dport 5060 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m state --state NEW -m udp --dport 5060 -j DROP
I've added a PREROUTING NAT rule that change the port from 5065 to 5060 for others - but then, this gets caught in the INPUT rule as port 5060 -A PREROUTING -p udp -m udp --dport 5065 -j DNAT --to-destination 192.168.1.1:5060
This works so well that the packets coming on port 5065 are translated to port 5060 and get caught in the DROP rule...
View 1 Replies
View Related
Jun 1, 2011
I have blocked all connection with iptables and allowed only the loopback:
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP
Next I want to allow only ssh connections, and also I want to record the IP address of each attempt to access port 22 using the recent module. Then I want to to see if that IP address has attempted to connect 2 or more times within the last 60 seconds, and if not then the packet is accepted:
iptables -A INPUT -p tcp --dport 22 -m recent --set --name ssh --rsource
iptables -A INPUT -p tcp --dport 22 -m recent ! --rcheck --seconds 60 --hitcount 2 --name ssh --rsource -j ACCEPT
iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --sport 22 -j ACCEPT
iptables -A INPUT -j DROP
iptables -A OUTPUT -j DROP
View 9 Replies
View Related
Jan 20, 2010
I get today a server with CentOS.. and someone told me to block access to port 22 for all IP's except my.. so I did
Code:
iptables -A INPUT -p tcp -s my_ip --dport 22 -j ACCEPT
and after
[code]...
View 7 Replies
View Related
Aug 14, 2010
I have a CentOS box which is Internet Facing. It has 3 LAN's connected to it which are for virtual machines.
I want to port forward port 445 to a machine on one of the LAN interfaces. I have tried various ways to get it done, but still cannot access that port from the interface. I definately know device hosting port 445 is live, as I can ping it from the CentOS box and use lynx to access it! (It's a web server)
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 445 -j DNAT --to-destination 192.168.0.2:445
View 6 Replies
View Related
Jun 7, 2010
I've been Googling about port forwarding iptables and even though there's result and I've applied it in my script, I can't make iptables forwading request to another machine so I decided to ask help.
eth0 is my Internet Interface (1.2.3.4 is the public ip)
eth1 is my Lan Interface
eth2 is my DMZ Interface
[code]....
View 14 Replies
View Related
