Debian Configuration :: IPTABLES Protocol To Reject All Incoming Ssh Traffic
Apr 4, 2010a good IPTABLES protocol to reject all incoming ssh trafiic except for a single IP or IP range?
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Ubuntu Networking :: Iptables: Block Incoming And Allow Outgoing Traffic
Jan 6, 2011I need to configure iptables to block incoming traffic (except specific ports), but allows all outgoing traffic.
I am able to block incoming traffic, but doing so also prevents outgoing traffic (tested by telnet [URL] 80)
The following was used:
iptables -A INPUT -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -I INPUT 1 -i lo -j ACCEPT
iptables -A INPUT -j DROP
Also, even allowing NOT SYN requests still prevents outgoing traffic.
iptables -I INPUT 1 -p tcp ! --syn -j ACCEPT
Another point:
# modinfo ipt_state
modinfo: could not open /lib/modules/2.6.18-028stab070.14/modules.dep
How to install ipt_state module on ubuntu?
Debian Configuration :: IPTables - Local Host Cannot Get Returning Traffic
Sep 20, 2010I have a strange iptables issues. I have just built a new Debian install and starting adding some real basic rules (see below) the problem seems to be that the localhost itself can't get any returning traffic. That is, it seems to be allowed outgoing traffic but not the connected, returning traffic. Ordinarily allowing Established Connections would resolve this, see the rule below, but it hasn't. Why this doesn't work. Removing the last DROP in the INPUT chains obviously makes the traffic work!
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -j ACCEPT -p tcp --dport 22
iptables -A INPUT -j ACCEPT -s x.x.x.x
iptables -A INPUT -j ACCEPT -s x.x.x.x
iptables -A INPUT -j ACCEPT -s x.x.x.x -p tcp --dport 80
iptables -A INPUT -j ACCEPT -s x.x.x.x -p tcp --dport 8080
iptables -I INPUT 1 -i lo -j ACCEPT
iptables -A INPUT -j DROP
Networking :: Postfix: Way To Reject All Incoming Mail?
Jun 26, 2010I'm using postfix on Ubuntu 9.10 and all I need is to occasionally send automated emails from perl or php scripts when data processing errors occur. In other words, I want to reject any connection attempts from remote clients and otherwise allow nothing except outgoing emails from one particular account.f I add this line to the default main.cf, will it do the trick or is it more complicated?
Code:
smtpd_sender_restrictions reject
Security :: Iptables State Module - Configuration Error / Not Enable Incoming Packets From Connections Initiated From Inside?
Mar 30, 2011I have a server that I can only access via SSH (it's located far away) and I would like to secure it by blocking all ports except the ones that I need (which are HTTP and SSH). I still want to be able to make outgoing connections to enable software updates and other things.This is my iptables -L -n :
Code:
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:1:21
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:23:79
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:81:65535
code....
In my opinion, this should block all incoming packets except the ones on port 80 and 22, but allow responses to outgoing connections. But a wget http://google.com does not work, it can't establish the connection.
Maybe this is not the best style for iptables rules, but I want to be absolutely sure to not accidently lock myself out from SSH, so I chose not to configure a "block-everything rule".
Does this configuration not enable incoming packets from connections initiated from inside?
Ubuntu Security :: Reject Versus Drop For Outbound Traffic
Apr 15, 2011I understand the difference between Reject vs Drop for incoming traffic, but are there any differences between reject and drop for Outbound Traffic? Are there reasons to pick one over the other or are they functionally identical when talking about Outbound traffic?
View 6 Replies View RelatedGeneral :: Iptables - Use DROP Instead Of REJECT And Vice Versa?
Jan 13, 2011When deleting a rule, when is better to use DROP instead of REJECT and vice versa? Also, please provide some basic info. for the use of MASQUERADE??
View 3 Replies View RelatedGeneral :: When Applied The Iptables Rule As Above Then The Mails Get Reject?
Mar 22, 2011I have configured a sendmail MTA for incoming mails in a network and by using IPtables i have redirected the traffic internally to other port where one more SMTP by a application is running.Iptables rule:iptables -A INPUT -i eth0 -p tcp --dport 25 -j ACCEPTiptables -A PREROUTING -t nat -i eth0 -p tcp --dport 25 -j REDIRECT --to-port 25000My sendmail config is as below.
Sendmail.mc
define(`SMART_HOST', `relay:host.subdomain.mydomain.com')dnl
dnl # define(`RELAY_MAILER',`esmtp')dnl
[code]...
Ubuntu Networking :: Loads Of Incoming UDP Traffic?
Jun 29, 2011My laptop has become very sluggish. So I loaded firestarter firewall. It is reporting loads of incoming UDP traffic. I only use this machine for Skype and Firefox based work as most of my stuff is kept on the cloud. Is it safe to stop all this UDP traffic? It would free up my CPU I guess. It seems port 56095 is getting hammered.
View 8 Replies View RelatedDebian Configuration :: Disable The Ip6v Protocol Permanent?
Feb 14, 2011Is there a way to disable the ip6v protocol permanent?
View 4 Replies View RelatedFedora Networking :: VLAN Not Recognizing Incoming Traffic?
May 29, 2011Before explaining the problem, I have to draw the environment. Because of post size limitations, I'll have to break this post in more than one entry.
Physical view
Code:
+--------+ +---+
|storage1|-----| |
+--------+ | s |
| w |
+--------+ | i | +-------+
|router2 |-----| t |-----|router1|--->Internet
+--------+ | c | +-------+
| h |
+--------+ | 8 |
|router3 |-----| |
+--------+ +---+
Device details
[Code]....
Ubuntu Networking :: Randomly Blocks Incoming Traffic?
Aug 5, 2010I am running the latest ubuntu. Sometimes it randomly stops accepting ssh connections, afp/smb connections, and even stops responding to pinging. It is connected via WIFI.
I go over to the desktop and use the browser, and the internet still works fine. Then after a while, it starts accepting incoming traffic again.
Networking :: Block All Incoming Mail Traffic Except Certain Addresses?
Jan 12, 2009assist me in using the iptables firewall to block all incoming mail traffic (SMTP port 25) except that of a certain IP(s)? the situation is that we have a server that we only want to receive mail from a particular sender.
View 1 Replies View RelatedUbuntu Networking :: Bridging Firewall - How To Block Incoming Traffic
May 2, 2010I have a ubuntu computer set up as bridge between gateway and lan, with the lan connected to eth0 and gateway on eth1.
I'm trying to get it to basically block everything incoming except for the ports i specify, but also allow outgoing traffic. I've found, tried, modified som examples i found on the web, but still it wont block incoming traffic (ie, im still able to reach my webserver)
These are the rules, and i can't figure out why it wont block:
Code:
#!/bin/bash
iptables -F
iptables -X
iptables -I INPUT -i eth1 -j DROP
[Code].....
Networking :: Routing Incoming Traffic To NAT'ed VM On A Hired Dedicated Server?
May 21, 2010I have set up a Virtual machine on a dedicated server from 1and1. I hoped to use a bridge to give the vm direct access to the internet but 1and1 do mac filtering and so the only option is to use NAT.
I used Virtual Machine Manager on my Ubuntu 10.04 machine at home to install Debain Lenny on the vm on the server using KVM and all went well. I put it on a virtual network 192.168.100.0 and i can access it from the host and i can access the internet from the guest using NAT that libvirt set-up.
I bought another ip address from 1and1 with the hope of forwarding packets to the new ip address 11.22.33.02 to the guest vm.
I have tried all sorts of routing rules using iptables without any success.
my virtual network is on virbr1 the guest ip is 192.168.100.50 my external network device is ip say 11.22.33.01 on eth0 with the secondary ip say 11.22.33.02 on eth0:1
Here are the latest rules i tried:
Quote:
iptables -t nat -A PREROUTING -d 11.22.33.02 -i eth0 -j DNAT --to-destination 192.168.100.50
iptables -t nat -A POSTROUTING -s 192.168.100.50 -o eth0 -j SNAT --to-source 11.22.33.02
iptables -A FORWARD -p tcp -i eth0 -o virbr1 -d 192.168.100.50 -m state --state NEW -j ACCEPT
iptables -A FORWARD -t filter -i eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT
[Code].....
Networking :: Trace Incoming And Outgoing Network Traffic For A Give User?
Mar 14, 2010OS : CentOS 5.3 64bit How to trace incoming and outgoing network traffic for a give user? User 'A' logs in to the system and does various network connectivity As root user need to find what are the outgoing and incoming connection that are related with user 'A'. basically need to check the connection flow. netstat will show ESTABLISHED, LISTEN etc.. need something like tcpdump
Eg:- --user option for tcpdump tcpdump -vv -nn -i eth0 host 10.200.2.1 and tcp dst port 8080 --user A Can someone tell me any tool which can do such thing? Even if it can show the process ID of the client application which is trying to establish network connectivity will do.
General :: Redirect Incoming Traffic To An Other Port (ubuntu Openvpn Server)?
Dec 5, 2010I have set up an openvpn server on ubuntu via port tcp 443. The server use a public network and almost every ports are blocked (not 443) So when a client connect to the server, if it send traffic needing a blocked port, the connection cannot been etablished of course. So i d like to know if it is possible to redirect all incoming traffic on the server to an other unblocked port (like 443) to bypass firewall.
I dont think openvpn offer this possibility but maybe with linux it is possible..
Debian Configuration :: Traffic Shaping Per IP
Sep 19, 2010I have a question regarding Traffic Shaping in Linux, Suppose I have a server on the internet (web, email or ftp) and I want to shape outgoing traffic per IP, say 256k for each destination IP. I've seen examples on the internet on how to shape traffic per IP by adding a queue for each IP, and some examples by using u32 hash if I have e.g. a /24 network, but if I have a server and I want to shape the traffic by destination IP, and of course... since it is a server on the internet I can't manually define any IPs of subnets. An example using the tc command?
View 2 Replies View RelatedDebian Configuration :: Traffic Bypasses OpenVPN
Sep 16, 2015I'm running OpenVPN service on both debian server and client. When start connection between client and server, I expect all the computer traffic (except ARP and DHCP requests) go through created tunnel. However, when I capture packets on wlan0 on client (the only connection going outside host) using Wireshark, I can see DNS requests visible and sometimes incoming TCP traffic as well, but most of the traffic is going through tunnel as expected. I provide both configurations of client and server and client routing table for inspection. I changed server address to avoid server exploitation in the case of some big configuration mistake.
Commands to run OpenVPN services are:
Code: Select allFor client: sudo openvpn --config /etc/openvpn/client.conf &
For server: sudo openvpn --config /etc/openvpn/server.conf &
**Client routing table when VPN is OFF**
Code: Select allKernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 1024 0 0 wlan0
192.168.1.0 * 255.255.255.0 U 0 0 0 wlan0
[code]...
I searched through many forums and documentation and I found, that for all the traffic going via VPN is command: *push "redirect-gateway def1"* neccessary, however, I have leaks despite this command being in place. I already spent over 2 days with this and tried to configure it in many ways, now I have no clue what I'm missing.
Debian Configuration :: Routing - Forward All Traffic To An Ip To Another Ip?
Jul 25, 2010I need to be able to do the following: Physical Router located at 192.168.40.1 On Ubuntu 10.04 Lucid machine:
eth0 with static ip 192.168.40.2
eth1 with static ip 192.168.40.3
eth2 with static ip 192.168.40.4
Associate a virtual address to eth1 with an entirely different network address such as 192.168.50.1 Do the same (virtual address) for eth2 -- e.g. 192.168.60.1 In the application:
register phone number A at 192.168.40.1 (The application will automatically use eth0 for this)
register phone number B at 192.168.50.1
register phone number C at 192.168.60.1
Somehow forward all traffic (including the register request) sent to 192.168.50.1 to 192.168.40.1 as if the register had been made directly to 192.168.40.1. In other words, the app "sends" registration and traffic to 192.168.50.1 but then Ubuntu forwards it to 192.168.40.1 (but the app does not know that). Similarly, forward all traffic sent to 192.168.60.1 to the router at 192.168.40.1.
Do the same for the reverse, forward all traffic that the router sends back to 192.168.40.3 (eth1) to 192.168.50.1 (within the Ubuntu machine) so that the app knows it is for phone B. Similarly forward all traffic that the router sends back to 192.168.40.4 (eth2) to 192.168.60.1 so that the app knows it is for phone C. Thus, the application believes that it is registering at 3 completely separate routers on 3 completely separate networks via 3 separate network interfaces but in fact is really registering all three to the same router (but does not know that). Similarly, the router believes that it is receiving 3 separate registrations because it receives each registration request and traffic from 3 separate interfaces and thus 3 separate mac addresses (i.e., of eth0, eth1, and eth2). Traffic sent to and from the router for each of the 3 phone numbers (via eth0, eth1, and eth2) are not mixed because the translation happens in both directions.
Debian Configuration :: Tunnel All Traffic Through PPTP VPN
Dec 12, 2010I installed the PPTP Client [URL] and can successfully connect to my VPN (creates interface ppp0). The problem is, I'm trying to tunnel all of my traffic on my system through the connection. I've seen conflicting howtos and scripts including pptpclient's documentation (the ip-up and ip-down scripts don't work). How does one simply (even if I type it manually) tunnel the traffic?
System Info:
OS: Debian Squeeze, Kernel 2.6.32-5-686
GUI: Gnome (standard one from netisnt unstable install)
Main interface: eth1
PPTP interface: ppp0
Networking :: Add The Rtp Protocol To Iptables Rule?
Jul 29, 2009i'm new in linux world i would like to know how can i add the rtp protocol to my iptables rule for Netfilter firewall,but without installing the asterisk server
View 1 Replies View RelatedDebian Configuration :: How To Modify Traffic Between Two Interfaces In Linux
Aug 8, 2015I have a laptop connected to internet via wlan0. I also have eth0 interface and with it I share internet. I want to modify/filter all the traffic passing by the first laptop, something like this:
Code: Select all *---------------------------*
| LAPTOP 1 | *--------------* ?
|-----* *------* *----* | |
INTERNET<------>|wlan0|<-->|MY_APP|<-->|eth0|<---->|ANOTHER LAPTOP|
|-----* *------* *----| | |
*---------------------------* *--------------*
I know that in FreeBSD it is possible to use ipfw for that purpose, because it build-in into kernel. We set for example rule Code: Select allipfw add divert 2000 ip from any to 1.0.1.1
and we can use our own application to process those packets, reinject them forward etc. It will work also fast, because as I said, it build into kernel.
Is there any standart Linux-based solution to do the same? I found some info about netmap-ipfw. Is this a correct solution? Or I have to use for example IP-aliases and iptables to do that?
I need to process all the IP-packets, not only TCP/UDP/etc-protocol. Solution also must be very fast.
Debian Configuration :: Redirecting Traffic Through SOCKS Proxy?
Aug 11, 2010I would like to redirect traffic coming from a machine A through a SOCKS proxy (setted on machine B)Machine B run "ssh -D 4242". So that create a SOCKS proxy on machine B.Machine A would like to connect on the internet, but the only way is to use machine B SOCKS proxy. The problem is machine A don't know how to use SOCKS Proxy. (Actually, i can just set ip, netmask and gateway on machine A).So, I would like to set up something on machine B that will redirect all traffic coming from machine A throught the SOCKS proxy.
View 1 Replies View RelatedDebian Configuration :: Torrent Traffic Very Slow / Make It Up?
Jul 10, 2011I am running on debian squeeze 6.0.2. I have been using it for the last id say 3 weeks and really am enjoying it.
I generally use transmission-gtk to share files over the internet. Normally I seed torrents at 110-160kb/s for hours at a time. However after messing around with firestarter my upload speed for seeding torrents rarely peaks over 70kb/s. I have purged firestarter with no success of my regular upload speed, and am very confused as to what happened. I also notice sometimes when it will get to about 70kb/s it will immediately drop down to the 20-30kb/s range.
For incoming bittorrent connections I use port 37294. I have set port 37294 to be allowed in my firewall, and forwarded in my router (since purging firestarter did not help I just reinstalled it).
I have also read allowing ports 6881-6889 is important, but I have never done that in my history of using torrents, and I have never experienced a decrease in UL speed like this.
Have I done something incorrect? I have never had this issue on other machines?
Networking :: What Protocol To Mention Rtmp In IPTABLES
Oct 22, 2010I am not clear if I should use tcp or udp for rtmp in IPTABLES. I am having a streaming server where I have this problem.
View 1 Replies View RelatedDebian Configuration :: Routng Traffic To A Website Via A Specific Interface
Jul 30, 2011I am running Debian Squeeze on an old pc (AMD K62-500) which serves as my multiwan router and torrent box. Internet uplink is provided via a dsl line and 2 wireless canopy modules.
Setup has been generally fine except when connecting/downloading as free user from sites like rapidshare, hotfile, filesonic, etc. The problem arises when I am connected to these sites using the wireless uplinks because of the shared public ip. I don't really download that much using direct download methods so I don't really see myself being a premium user from these sites.
If these sites are on a specific ip or ip range, an entry on the static routing table would have been fine but when I tried using ping, a different ip would appear to reply each time.
I wonder if there can be a solution like using iptables where in traffic to and from these sites will only use the NIC connected to the dsl line.
Networking :: Setting Time For IPTables To Remember Its Incoming Port?
Mar 9, 2010I've got a box with 2 interfaces, with IP1 = 192.168.100.1 and IP2 = 10.1.1.1 respectively on them. I've got an iptables rule that looks like:
Code:
iptables -t nat -A POSTROUTING -s 192.168.100.0/24 -d 10.0.0.0/8 -p udp -j SNAT --to-source 10.1.1.1 --random
If I get 2 consecutive packets from the same address and port from 192.168.100.0/24, they get SNAT-ed and come out of the same port on 10.1.1.1. If then I get another packet from the same address and port 10 minutes later, then it gets SNAT-ed, but comes out of a different port on 10.1.1.1. How can I set the time delay I would like iptables to remember its incoming address/port to outgoing port mappings?
General :: IPTables Drop Or Forward Host (Incoming Connection)
May 3, 2010How can I drop or forward a incoming connection from a part of a host like *.alicedsl.de
For example:
The user is connection from *.alicedsl.de on port 12345
So how can I drop this connection or forward to google.com on port 80
Security :: Limit Incoming HTTP Bandwidth Usage With IPtables
Apr 5, 2011Can I, with only the use of IPTABLES, limit the incoming bandwith for a protocol? We have for example servers that have a FTP and HTTP server running and whenever HTTP has a lot of connections open, the other uploads/downloads get a timeout. I know I can limit the number of connections but prefer to limit on protocol level. Is this possible using IPTABLES and if so, can someone indicate how to proceed or provide a link? If it's not possible can someone point me to the right tool for the job?
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