0
votes
0answers
26 views

Connect two servers with RJ-45 cable and iptables (without switch!)

I have two servers and server_1 is connected to INTERNET port (of server farm) at eth0. No switch. They connected with cable from (server_1)eth1 -> (server_2)eth0 : ifconfig of (server_1): eth0 ...
0
votes
0answers
28 views

Linux Server as Router using IPtables Don't Forward IP traffic [closed]

Currently, I'm trying to setup based on Ubuntu 14.04 LTS router like solution. I don't have much alternatives available, so I will use linux box as a router. Current Config (machine is virtual ...
-1
votes
2answers
28 views

Forward Clients to New Server using iptables

Clients are connected to a server A by connecting to the domain name address www.example.com:4444, where www.example.com resolves to the IP address of server A. Question: In order to provide a ...
0
votes
1answer
57 views

Multi-homed network?

I have a network with a layout like this: ******* ****** ******* ****** * SW1 * --------- * R1 * ---------- * SW2 * ---------- * R2 * ******* ****** ...
-1
votes
1answer
49 views

How should I properly block outgoing http traffic with iptables

I'm experimenting with iptables, and I'm trying to allow all outgoing requests for HTTPS, but to block HTTP. I have the code below; Chain INPUT (policy ACCEPT) target prot opt source ...
0
votes
0answers
32 views

OpenVPN in bridged mode, confusion about interfaces

I'm trying to understand some fundamental OpenVPN/networking basics. Let's assume the following scenario: there is an openVPN server which is already configured properly it runs in bridged mode the ...
0
votes
0answers
28 views

Why can't some user accounts access certain remote ports?

I am trying to troubleshoot a couple issues on RHEL 6.5 that seem related. In both cases, a user on a machine (seperate machines) cannot access a service (seperate services) on a remote machine. In ...
0
votes
1answer
30 views

Using OpenVPN and iptables in combination

Let's imagine there are three networks, WAN, LAN-A and LAN-B. In between, there is a firewall server connecting the networks to each other. iptables ensures the following things: There is no way for ...
0
votes
1answer
85 views

Is it possible to make the server accessible from two internet connections

how to make this: have: Centos 6.5 WAN1 eth0 44.44.44.44 (DEFROUTE=yes) WAN2 ppp0 95.95.95.95 (DEFROUTE=no) HTTP server work and available only in eth0 DNS server work but port 53 blocked in ...
0
votes
0answers
44 views

Iptables INVALID packet from akamai and google to linux

I set up the firewall rules below (I also blacklisted the IPV6 Module): iptables -A INPUT -m conntrack --ctstate INVALID -j LOG --log-level debug --log-prefix '[FW INVALID]: ' iptables -A INPUT -m ...
-5
votes
1answer
35 views

How to route to next server? [closed]

I must route all traffic from first server to second server and next to third server. Like this: server1 -> server2 -> server3 I use Debian Wheezy. Can anyone tell how to do this with iproute?
0
votes
1answer
34 views

Unable to get out of rescue mode after a spontaneous reboot

I am experiencing a weird problem where the CentOS 6.5 system I was using spontaneously underwent a restart that was not authorized by me, and then enters Rescue Mode, where I am unable to diagnose ...
1
vote
1answer
143 views

How to stabilish a VPN connection, only on port 8080

Infrastructure: Here's what I want, be able to connect to the website 10.10.100.32:8080 from my LAN on 'Router 1', and all the traffic outside the port 8080 should go to the default gateway 'Router ...
2
votes
1answer
53 views

nftables alternative for iptables -F

Simply, is there any quick alternative of iptables -F command (that just "deletes everything") for nftables? Such thing wouldn't have much theoretical purposes, but it's usually a lifesaver for ...
0
votes
3answers
208 views

Routing between two subnets using a Linux box with two NICs

I have a Linux box with two NICs, each connected to a different LAN: Network A: 192.168.1.0 255.255.255.0 Network B: 192.168.2.0 255.255.255.0 The routers are: 192.168.1.1 192.168.2.1 Linux NICs are ...
0
votes
1answer
82 views

Block ip forwarding for specific remote ip address

I use ubuntu as gateway for several hosts. I need advise how to block ip forwarding for specific ip address or specific ip range? I tried to block ip via ufw deny rules, but it looks like ip ...
0
votes
1answer
85 views

Why does installing vzctl on a fresh Centos6.5-minimal break network connectivity?

I seem to have encountered a bug in vzctl's installation. Upon installing it in a clean CentOS6.5-minimal installation according to the official wiki, network connectivity is limited to pinging IP ...
1
vote
0answers
54 views

Firewall and NAT settings in GSM modem for one server

I have a GSM Modem (PSI-MODEM-GSM/ETH) in field with one device behind, acting as a server. The situation is as follows: "PC" | \_________Dynamic IP: 10.103.153.122 | ...
-4
votes
2answers
46 views

How to manage PING replies? [closed]

How can I manage, for example, my Ubuntu mashine so it doesn't (or does) respond to PING(ICMP ECHO_REQUEST - type 8) requests? Normally almost all computers in a LAN network responds to ping with an ...
0
votes
0answers
97 views

debian multiple network interface multiple networks

I have a virtual environment with 3 virtual machines on one host. One of my virtual machines has 2 network interface. I need the virtual machine with two interfaces to connect to two different ...
1
vote
1answer
41 views

Accessing a container from another container using the public IP of the host

I've some issues configuring properly the network in proxmox. In short, from a container, I can reach any web server outside (ex: google.com), but I can't reach the web server on my container. The ...
4
votes
2answers
268 views

packets sent on virtual IP don't hit iptables rule

I have a virtual interface eth1:3 with IP address 222.192.124.3, I have set up an iptables rule to log packets coming on that interface using the interface's IP (I know iptables doesn't care about ...
0
votes
1answer
103 views

Network remapping with iptables and PPTP VPN

I have two different networks: Home network 192.168.1.0/24 A - Home PC (192.168.1.100) B - Home Router (192.168.1.1 lan ip - x.x.x.x public ip) Office network 192.168.1.0/24 C - File Server ...
0
votes
0answers
57 views

Couldn't load target `DNAT':No such file or directory

Trying to do some ipv6 nat and running into an error from ip6tables $ip6tables -t nat -N IPV6-BRIDGE $ip6tables -t nat -A PREROUTING -p all -d 2600:3c01::f03c:91ff:fe6e:2563 -j IPV6-BRIDGE $ip6tables ...
0
votes
0answers
37 views

Pinging to google.com from a particular interface

I am connected to the internet via wlan0(wifi) and also have an ethernet port(not connected to the internet). I am looking for some iptables rule / route addition, which will let me do a ping via eth1 ...
-1
votes
2answers
64 views

Suspect traffic from 185.0.0.0/8 [closed]

I have a server/gateway running Debian 7. There is a big incoming traffic (for a homemade server) from an ip address located at 185.0.0.0/8 network for more than 40k packets in 24h. I have blocked all ...
9
votes
2answers
822 views

linux command to prevent dos attack by using netstat and iptables

I want to DROP more than 200 requests per ip to prevent ddos attack. this is command that i used to detect requests count per ip : netstat -alpn | grep :80 | awk '{print $5}' |awk -F: '{print ...
0
votes
1answer
48 views

Blocking incoming traffic for interface

I have created an interface eth0:2 and I want to make curl requests from that interface only so I want to block all ports and incoming traffic on that interface. This iptables rule used to work, but ...
0
votes
1answer
61 views

IPTables: Firewall with just one Eth device? [closed]

Admittedly I am a novice in the area of firewalls. But I have read on the IPtables and Firewall theory and command options. There is a general diagram by Rusty Russell, the creator of IPtables: ...
1
vote
0answers
45 views

OpenVPN running on Internet Gateway, so all private clients can access VPN with no config

Our LAN connects to our office gateway machine (192.168.1.1), which is connected to the Internet. I have setup NAT/Masquerading for this purpose with no issue. We also use OpenVPN to connect to our ...
0
votes
1answer
65 views

How can I configure iptables to forward and forget?

I'm trying to create a front controller where users can connect to a specific port and have their connection redirected to a different IP/port. The reason I'd like to be able to do this is for ...
1
vote
1answer
70 views

how to forward proxy requests using iptables

I've this schenario ----------------- ---------------- ---------- | SERVER A | ---(port:2128)> | PROXY | ---> | INTERNET | | (10.30.1.1) | ...
0
votes
1answer
91 views

Cannot close Port 25 after installing postfix

Before installing logwatch (which installs postfix) on Ubuntu 12.04, the port 25 is blocked by iptables/csf PORT STATE SERVICE 25/tcp filtered smtp After installing logwatch (which installs ...
-2
votes
2answers
56 views

How to block access to a local user to a local port?

How to block access to a local user to a local port? Example: user Elvis should not have access to the port 25600 on the same server.
0
votes
1answer
126 views

some outgoing http connections fail

After a recent reboot, my server is unable to connect via http, but not all the time. I have an accept rule for port 80, here is my iptables: Chain INPUT (policy ACCEPT) target prot opt source ...
0
votes
0answers
124 views

xen and port forwarding from dom0 to domU

I have a server running Xen with the following network configuration root@ubuntu:~# cat /etc/network/interfaces # The loopback network interface auto lo iface lo inet loopback auto xenbr0 iface ...
0
votes
1answer
51 views

How to access two separate web servers via a Linux Gateway running IP tables

I have two Ubuntu 12.04 servers. Server 1 acts as the firewall using IP tables and hosts the Proxy server. Server 2 hosts the web server. I have an external ip address terminating on eth1 on Server ...
3
votes
3answers
420 views

Can't stop DDOS [duplicate]

I need a little help dealing with ddos. I'm experiencing 1gb ddos attack on my server and I don't know how to stop it. (1gbs is the maximum speed of the server.) I've the following iptables rules: ...
1
vote
1answer
161 views

Access web server on VM from a machine in a different subnet

I cannot access to a web application running on a virtual machine hosted by KVM from a machine in a different subnet. So, I would like to access from the machine 192.168.1.2 (top right in green ...
0
votes
0answers
78 views

How to set mark on packet when forwarding it in nat prerouting table with rp filter 0?

I have a serious problem with my server ubuntu 13. I have two ADSL lines and an internal network as follows. i.imgur.com/v4ddHXf.png (URL IMG) IP redirections made ​​two because there are two older ...
1
vote
3answers
809 views

iptables error: unknown option --dport

The command iptables no longer recognizes one of the most commonly used options when defining rules: --dport. I get this error: [root@dragonweyr /home/calyodelphi]# iptables -A INPUT --dport 7777 -j ...
0
votes
0answers
141 views

Dropping packets with Open Vswitch and OpenFlowControl

I am trying to setup some Flows with ovs-ofctl to block all unwanted incoming packets for a VM. The commands I use are: ovs-ofctl add-flow xenbr0 "priority=65000, table=0, tcp, dl_src=*, nw_src=*, ...
0
votes
4answers
64 views

What can be done to migrate network applications when the client configuration cannot be changed?

We have a number of situations where a client application needs to be migrated from one host to another in an active production network. The servers continue to run other applications. The problem is ...
0
votes
1answer
129 views

Access Nginx by 127.0.0.1 works fine, but access by IP return 400

I deploy Django+uwsgi+Nginx project, but access nginx by 127.0.0.1 works fine, 400 returned if access by IP The iptables shows # iptables -L |grep 8181 ACCEPT tcp -- anywhere ...
0
votes
3answers
176 views

CentOS masqueraded network with iptables clients not connecting: Unable to ping

I'm a novice sysadmin working on a system with a CentOS server masquerading traffic with client machines also running CentOS. Something with the tables got messed up and my clients no longer have ...
1
vote
2answers
94 views

How to best redirect customers to a login page? (ISP)

I'm trying to come up with the cleanest way to redirect a user to a logon/payment page from an ISP gateway router. We run a small ISP and would like to force users to have to log in prior to getting ...
1
vote
2answers
191 views

Reach LXC container from a virtualbox guest on the same host

Context I develop websites on my Ubuntu laptop (Ubuntu 13.04 64b). Each site runs within a dedicated LXC container¹ on network 10.0.3.x I sometimes need to reach those sites from a virtualbox guest ...
1
vote
1answer
97 views

copy ipv4 rules to ip6tables

I have a static IPv4 and a static IPv6 address. Right now, my iptables look like: *filter :INPUT DROP [28:2168] :FORWARD DROP [0:0] :OUTPUT ACCEPT [551:134808] -A INPUT -i lo -j ACCEPT -A INPUT -i ...
0
votes
0answers
33 views

CONNMARK on rewritten packets

I have tried to ask this question on superuser, for it, being a custom setup, belongs there, but that got no answer even with a bounty. I have a host, on which I rewrite saddr and daddr of IP packets ...
0
votes
1answer
126 views

How to add another router on an existing subnet? [closed]

What I am trying to do is basically this. I am on a network who's routing table is something like this. Destination Gateway Genmask Flags Metric Ref Use Iface default ...