Iptables is a module that provides the Linux operating system functions of firewall, NAT and logging of data traveling over a computer network.

learn more… | top users | synonyms

0
votes
0answers
435 views

IPTables NAT and virtual interfaces

I have 2 VM's running CentOS 7 with the following ifconfig configurations: VM1: ifconfig eth0: public ip eth0:0: LAN IP 172.22.xx.x1 VM2: ifconfig eth0: no public ip eth0:0: LAN IP 172.22.xx.x2 ...
0
votes
0answers
214 views

Opening the Postgresql port

I'm trying to connect to a Postgresql server from a remote computer using: psql -U dbuser -h [host address] But I get the following error: psql: could not connect to server: No route to host Is ...
0
votes
0answers
23 views

Hostapd does not process HTTPS trafic from ppp0

I setup router server with hostapd 2.3 which works perfectly with eth0 -> wlan0 configuration. But if I'm switching config to ppp0 -> wlan0, then clients connected to wlan0 can access only to HTTP ...
1
vote
1answer
1k views

Squid 3.3 Transparent IPv4 and IPv6 Proxy with TPROXY

I'm attempting to change my Squid transparent setup from using generic NAT that's limited to IPv4 only and switching it to TPROXY, for IPv6 support. I'm having difficulties getting transparent clients ...
1
vote
0answers
186 views

Can't ping server itself after connected to PPTP VPN

I've set up a PPTP server on a CentOS 6.5 machine to use VPN from public networks and other miscellaneous scripts. Everything seem to be working OK except I can't ping the VPN server by its public IP ...
0
votes
0answers
102 views

Policy based routing with uid (ArchLinux)

Desktop (ArchLinux) with 1 physical NIC wlp0s29u1u5 connecting to the Internet. There is then a Openvpn client run on it as tun0. How can I make it that user (uid 1000) traffic only uses tun0? I've ...
0
votes
0answers
364 views

Cannot open pritunl port to outside

I'm trying to install pritunl on my Ubuntu 14.04 VPS, I managed to open port 9700, so I can connect to the web interface, my VPN should be running on port 16118, but for some reason I am unable to ...
0
votes
1answer
607 views

Mark packets with iptables by destination mac address

I need to mark packets which goes to a specified mac address. I need this to use in shaper with tc. --mac-destination doesn't exist in iptables. Also I tried to use ebtables: ebtables -t nat -A ...
1
vote
1answer
629 views

Check for packets MARKed by iptables

I am marking TCP and UDP packets in order to send them to two different interfaces (say wlan0 and eth0), I did this by following this answer. Assuming this configuration: eth0 address: 192.168.0.84 ...
0
votes
0answers
32 views

iptables linux - open all ports/everything for few servers and close everything from other servers

I want to open all ports (everything) for few servers and close all traffic incoming from any other server. iptables -A INPUT -s <ip of server1>/24 -p all -j ACCEPT iptables -A INPUT -s <ip ...
0
votes
0answers
57 views

Iptables in DD-WRT

I have a WRT54GL router with DD-WRT connected to (in the same VLAN): IP radio with very low bandwith (192.168.1.107) Arduino with Ethernet Shield sending UDP messages (192.168.1.110) Another router ...
0
votes
0answers
92 views

Using pptpd with iptables and interface ppp0

I already asked this stackoverflow, but I was told to ask it here :) I'd like make a few ports only accessible via VPN (PPTP). I'm running Debian 8 on the server and pptpd v1.4.0 from apt-get and ...
0
votes
0answers
272 views

Route all traffic of several VMs through a specific VM

I want to setup 3 VMs such that VM1 and VM3 can only talk to each other through VM2. So basically, all the traffic from VM1 and VM3 needs to be routed through VM2. VM2 then forwards the traffic or ...
0
votes
0answers
124 views

How to block HTTP 302 redirection package by matching a specific string on Location?

The HTTP response I want to block has: Header HTTP/1.1 302 Found Location: http://www.yxjiaodai.com/ad/?id=1023&url=http%3A//a1819.oadz.com/link/C/1819/3081547/dtMdon4l79FwsIo2JXEHqtdp5eQ_/p007/...
0
votes
1answer
172 views

What are the security risks of connecting to a VPN?

Does connecting to a shared-IP VPN expose local ports to other users of the same VPN server? Does a VPN tunnel neutralize the protection offered by a NAT router? Are local ports reachable from a ...
0
votes
0answers
173 views

Error when configuring iptables while setting up OpenVPN on Raspberry Pi

I'm in the process of setting up OpenVPN on my Raspberry Pi. Not sure if this is the right forum to post this but when I was trying to configure iptables i get this error message. Any thoughts? Thanks....
1
vote
0answers
89 views

OpenVPN and port translation

So, here's the deal. I have an openvpn instance on a port 443. I need it to also be on port 993, the same instance, the same virtual network. Openvpn can not really do that, but Linux comes with ...
-1
votes
2answers
60 views

how to verify firewall rule for a particular service?

How could i check which firewall rules are used by a particular service and whether port is blocked to restrict access by external users? i.e netstat -tulnp | grep 123 udp 0 0 0.0.0.0:...
0
votes
0answers
39 views

transfer ARP on linux iptables with diffrent subnet

Firewall(linux) - with 2 interfaces: internal, external ; also used as GW Internal: 192.168.254.1/16 External: 10.0.254.1/16 external_client(linux) IP: 10.0.1.1/16 internal_client(linux) IP: 192.168.1....
1
vote
0answers
37 views

How is Windows ICS service different from Linux-based NAT & routing when I want to hide my LAN structure from ISP?

Background I've been using a WIFI-router as my home gateway perfectly until my ISP appears to restrain the number of connected devices. And currently there is not any realistic upgrade plan from the ...
0
votes
1answer
52 views

Giving a local machine an external static IP ( can be just forwarded ports)

I've planned to make one of my home machines to be a mail server I can receive mail from other people on. I have a domain name for it, and I know I need a machine with a static external IP so I have a ...
0
votes
1answer
145 views

can't telnet on port 5433 on localhost after iptables stop

I'm trying to do a telnet localhost 5433 on my RHEL box but I get a connection refused error. I did a service iptables stop but am still getting the same error. Where else do I need to look to allow ...
0
votes
1answer
32 views

I need to block the POP3 DELE Message by IPtables - Linux

I installed the iRedMail (Postfix, Dovecot, ....) and create Mailboxes for Users. But I hanged in the Deletion Request. I want to prevent vUsers (that have MAilboxes) from deleting the eMails (...
1
vote
1answer
73 views

iptables is treating traffic from different hosts differently in spite of rules

Something spooky is happening here and I don't know how to fix it. Summary: traffic that appears identical to tcpdump is being treated by iptables differently. Details below. Test setup: device ...
0
votes
0answers
42 views

iptables config to restrict dhcp trafic

eth0 is connected to internet, and eth1 is connected to clients, giving dhcp addresses. However, I've got some clients getting IP addresses via eth0. Is there a way to put a line on iptables dropping ...
1
vote
1answer
446 views

Is it possible to setup a NAT loopback on a router with a dynamic IP using iptables?

I've set-up a Raspberry Pi home server attached to my router. I have a dynamic IP. I can access the server within my network using the internal IP (192.168.0.8). I can also access the server outside ...
0
votes
2answers
313 views

Opening port in iptables doesn't work

I add the following line before COMMIT in /etc/sysconfig/iptables: -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT Then I use service iptables restart to restart iptables, but the ...
1
vote
1answer
76 views

allow specific port past VPN while denying all other internet access

I have a local machine that connects to a VPN for internet access, and is configured so that it can't access the internet at all besides through the VPN, although the local network can be accessed ...
1
vote
1answer
444 views

Can't ping Subnet A from Subnet B with router between them

I experimented with subnetting in my home network and Raspberry Pi. The ISP Cable Modem has 4 eth-interfaces and 1 wlan interface which all seem to be switched together. The routers IP is 192.168.0.1 ...
0
votes
0answers
135 views

Securing bridged lxc container with iptables

For some reasons I need lxc containers which have the same IPs like the host itself and other computers in the internal network. Now, I setup so far the containers with a bridge which routes to veth ...
1
vote
0answers
168 views

Can I track the CPU load that IPTABLES firewall is causing?

Since IPTABLES is a software based firewall, I am wondering if it is possible to log the exact load it is causing, cpu cycles, etc. On a small system I am sure it is trivial. But how about with ...
0
votes
1answer
143 views

Can't Access Port number 80 and 443 after adding Iptables rules

In my CentOS 6 i added a IPtables rules like DROP all the policy like iptables -P INPUT DROP Then I allow Port NO 22,80,443 with this command, iptables -A INPUT -i eth0 -p tcp --dport 80 -j ...
1
vote
1answer
558 views

OpenVPN without NAT

I'm trying to figure out how to route OpenVPN clients without using NAT/PAT. What I want to do is to route the IP address that they are assigned when clients authenticate to the OpenVPN server to the ...
1
vote
0answers
41 views

Iptabes and PSAD [closed]

I have a couple questions regarding my iptables configuration. First off I am still relatively new to iptables configurations, I am going over guides and books but progression is slow. When I ...
1
vote
0answers
151 views

Too many connections from other IP addresses and my own IP address

I get thousands of connections from same IPs. It takes down my web server (Apache). How could I restrict 1 ip to open only 10 connections max using ip table rules? My 2nd issue is there are so many ...
1
vote
2answers
233 views

Linux - redirect SSH on a port to another machine on local network

I have a KVM guest machine on a virtual network. It has an IP address like 192.168.122.65. The host machine is connected to the public internet. If I open a terminal on the host machine, I can SSH ...
0
votes
0answers
15 views

Can't access my FTP Server due to change in value of IP_MODULES in iptables_config file

I could once access my FTP server usinf FIleZilla (FTP CLient) but couldn't upload files into it successfully. After trying the chmod 0777 and chown options and still couldn't upload files. I searched ...
2
votes
1answer
63 views

Netfilter/tc rule to separate SSH and SFTP traffic?

When I connect to my server (RasPI 2 with Raspbian) remotely, I want my interactive SSH sessions to always have priority over any running SFTP sessions. Also, SFTP sessions should have less priority ...
0
votes
0answers
90 views

Linux: Don't allow any non-vpn traffic

I tried the search, as I'm sure this has been asked before, but I couldn't quite find a working answer. I wish to drop any connection that is not routed via VPN (with the sole exception of the ...
-1
votes
1answer
162 views

Stopping multiple IPs from getting logged on iptables log

I want to log all dropped packets with my iptables (by default all except ssh), but I want to exclude the local network IPs as well as 0.0.0.0, 255.255.255.255 and 192.168.0.255 from appearing in the ...
0
votes
0answers
154 views

iptables not able to load conntrack match

I have a problem using iptables like this: iptables -m conntrack iptables v1.3.8: Couldn't load match `conntrack':File not found Now I wonder how I can debug this. This is what I have tried. ...
1
vote
2answers
82 views

iptables on CentOS 6.6

I'm trying to open a port on CentOS, but it doesn't seem to work: port 16 seems to be closed and 4075 seems to be open, even though according to iptables it should be visa versa. Chain INPUT (policy ...
3
votes
0answers
38 views

How can I read out the value of internal counter inside IPSet

I know there is an option named “counters” when creating an IP set with IPSet. However, I want to know how to read the value of the counters out, so as to know how many packets or how much data has ...
1
vote
0answers
63 views

Most efficient way to proxy a port from one host to a port on another

I have a host with one IP address which is using port 443 (HTTPS) with one certificate. I want to run a second app on this IP address using a different certificate on a different port. To prevent ...
2
votes
1answer
728 views

Routing subnet to specific routing table with fwmark, direct to ISP and VPN

Introduction I'm trying to set up a VPN on my router so that I have two routing tables. I want it so that all the filtering is done with iptables, and iproute just acts on the specific fwmarks, ie ...
0
votes
0answers
86 views

RaspberryPI OpenVPN Client Not Forwarding to tun0

reposting from the RPI SO - apparently off topic for Server SO... I found plenty of guides for how to run RPIs as OpenVPN servers, but I want to run it as a client. I have a OpenVPN server set up ...
0
votes
1answer
44 views

3 interface server - wap with bridge - how to route this?

I have the following setup (except the "server-addressed packets"-part): http://www.directupload.net/file/d/4062/jo9qswvv_png.htm Basically eth0, eth1 and a wap. eth1 and wap are bridged with br0. ...
1
vote
0answers
196 views

Error mounting NFS unit between synology server and Raspberry Pi client

I'm trying to mount an NFS (v4, or v3.. but get the same error...) from a Synology Server to a Raspberry Pi client. But I get this error: mount -t nfs4 IP_address_of_server:/volume1/nfsnvf /mnt/...
0
votes
3answers
342 views

SSH port block: port forwarding

I need to access SSH on machine A within another port than 22, because there are only the standard ports allowed to access from the network I use. Therefore, I want to route port 443 of machine B to ...
0
votes
0answers
48 views

Forward VOIP phone on eth1 over OpenVPN (tun0)

I have a remote computer connecting to my network via OpenVPN. This computer is running Linux Mint, and has two network cards: eth0: used for Internet connection eth1: has a VOIP deskphone plugged ...