0
votes
0answers
15 views

how to use --rdest flag in recent table

Here is why I try to accomplish: When receiving a UDP packet, put IP address of the source address in recent table. sudo iptables -A INPUT -p udp --dport xxxxx -m recent --set -j ACCEPT When send ...
-1
votes
1answer
39 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 ...
3
votes
1answer
24 views

Linux NFLOG - documentation, configuration from C

Several different places (e.g. http://wiki.wireshark.org/CaptureSetup/NFLOG) recommend using Linux's "NFLOG" firewall module to capture packets generated by a particular UID, like this: # iptables -A ...
0
votes
0answers
23 views

Restricted logins + almost all ports closed : secure? [migrated]

Context : I plan to travel. I want to make a little cloud with my personal server. I wish I could d/l some of my files and eventually upload some files which will not be executed and the whole is ...
0
votes
2answers
42 views

Forward SSH request to an External Server to an Internal Server

I have a VM config currently where I have 1 external IP pointing to a VM with an Nginx HTTP Reverse proxy serving HTTP Web Pages from several internal VMs without external IPs. I need a similar setup ...
-1
votes
0answers
27 views

DHCPREQUEST Operation not permitted

I am configuring iptables on a Ubuntu 14.10 VPS. However, I am having a few issues with the following: Jun 25 08:28:23 www dhclient: DHCPREQUEST of 1.2.3.4 on eth0 to 2.3.4.5 port 67 ...
1
vote
1answer
25 views

NIDS on bridged firewall

I have a firewall (Debian Stable 7.5) which works in bridged mode. The interfaces eth0 (WAN) and eth1 (LAN) are linked with the bridge interface br0. Can I deploy a NIDS (eg. Snort) on this server? ...
0
votes
1answer
18 views

Block an outbound destination IP to prevent connections waiting timeout duration [duplicate]

It seems like with the basic "DROP" iptables rule, an outbound attempt will still wait the duration of its timeout. For instance, if I block an IP address outbound, then attempt to connect to it via ...
-2
votes
1answer
25 views

Allow outgoing connections for DNS [closed]

I'm new to IPtables, but I am trying to setup a secure server to host a website and allow SSH. This is what I have so far: #!/bin/sh i=/sbin/iptables # Flush all rules $i -F $i -X # Setup default ...
1
vote
0answers
98 views

ClearOS Proxy - Block all traffic but two sites and 3 DMZ ips

I've been trying to two days now to get ClearOS to do a proxy setup for my network. This is what I need to do: I need to block all outgoing traffic no matter what it is, all ports and HTTPS as well ...
0
votes
2answers
72 views

Hardware firewall for Linux web (and mail) server allows UDP connections to any local port from remote ports 53 and 123 — is this safe?

I'm trying to tighten security on a linux web server. It has a hardware firewall with a default rule set and I noticed two rules that concern me: remote port: 123; local port: ANY; protocol: UDP; ...
0
votes
1answer
53 views

Can't connect to remote server. Socket error = #2000

I don't know what went wrong, but I get a Timeout after logging in to the proftpd server. STATUS:> [12.05.2014 16:30:24] Getting listing ""... STATUS:> [12.05.2014 16:30:24] Resolving ...
0
votes
1answer
66 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
81 views

iptables dual stack - ipv6 not working

I have problem with my iptables setup. I want to have completely dual stacked server so I use same rules for IPv4 and IPv6. However all IPv6 connections are just being dropped while IPv4 are working ...
0
votes
0answers
53 views

Multiple gateways with linux on same subnet using single NIC

I have the following configuration; Firewall 1 (site 1); x.x.x.x/26 subnet on external 10.0.0.0/8 on internal (internal IP 10.0.0.10) Firewall 2 (site 2); x.x.x.y/26 subnet on external 10.0.0.0/8 ...
2
votes
1answer
50 views

iptables: does a scanner knows if you DROP packets?

I know how REJECT and DROP chain works. But, as I read here REJECT vs DROP when using iptables, user Dagelf said that the server still replies with TCP SYN/ACK. Does the scanner knows that a packet ...
0
votes
0answers
67 views

Force all traffic through VPN

I am using PfSense as a firewall, with its VPN functionality. The client I use is Shrew Soft VPN client. As it is a split tunnel, is there a way I can force all traffic through the VPN connection, ...
0
votes
2answers
203 views

IpTables Configuration Not Working to block ports (Centos 6.2)

I am trying to only allow certain IPs to access port 8209. I have tried a few different methods that I read on ServerFault. This method is the most recent one I have tried. I manually edited my ...
0
votes
1answer
51 views

Forward a port to another server using iptables

I have a server that is configured to block any port, and exceptions are configured like this (for mongo): iptables -A INPUT -p tcp --dport 27017 -s 10.20.1.0/8 -j ACCEPT ...
0
votes
1answer
32 views

change timeout for dropped ip traffic

I am behind a corporate firewall, which simply drops (swallows) all ip-traffic to unknown ip-addresses. It takes a lot of time for Linux (Ubuntu 13.10) to abort my erroneous connection-attempts, ...
0
votes
1answer
56 views

Turn IPTables Flush off CentOS

I made some changes to my iptables in a centOS machine. I noticed once I shut the server off it flushes all my iptables and goes back to the default. Is there a way to turn that off?
2
votes
1answer
122 views

connected to Centos openvpn but no outside internet access

I am using Windows 7 to connect to a VPS server running CentOS 6.4 First off, I have read every single post and just cant find the solution to my problem I configured my VPN server with openvpn, and ...
0
votes
1answer
82 views

Ubuntu 10.04LTS Server under attack, random reboots UNTIL I blocked China

What could have been sent to my server to cause it to reboot? Details: I have a for-internal-use LAMP server running Ubuntu 10.04LTS (upgrade is scheduled for that nebulous "when I have time"). It ...
0
votes
1answer
91 views

Configure atftp server to reply on port 69

Problem : I'm facing to a problem with TFTP server and Cisco 79XX IP phones. When on a local network, everything is working fine, but when the TFTP server is on a public server (and phones inside a ...
-1
votes
1answer
39 views

Firewall Connections fail to open under load

Problem : During High load , our applications are encountering errors : java.net.connection Time out. After some investigation , we found out that it was Firewall the root cause, but still don't know ...
4
votes
4answers
269 views

Why on linux machines, any packets do not pass except icmp, but correctly pass on windows

There is a cluster on proxmox. In a cluster have vm - configured router (pfsense). In the our net have Windows and Linux machines. There is the problem: Windows-machines have access to the internet, ...
0
votes
1answer
181 views

Point fail2ban to new log, without losing current bans?

I have logs in /var/log/syslog/YYYY-MM-DD/file.log files. New directories are created automatically by rsyslog, and logs are automatically put to new locations. Every day, I archive previous day of ...
1
vote
1answer
198 views

Is IGMP multicast traffic to a Xen VM host legitimate?

I run two Xen/CentOS 6.5 based VMs, both hosted by the same company, but connected to different networks (basic /24s w/ a single gateway at .1) in different physical locations. I developed an iptables ...
1
vote
3answers
749 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 ...
1
vote
0answers
154 views

Vyatta Remote Access VPN firewall (PPTP)

I am using Vyatta Remote Access VPN (PPTP) and NAT for proxy. When pc-A and pc-B are connected to VPN, pc-A ipaddress is 192.168.10.10 and pc-B is 192.168.10.11. ...
3
votes
1answer
81 views

Smart solution for XenServer firewall?

I've been searching for a smart solution for a XenServer firewall for about a month now. The documentation for the new default networking backend "openvswitch" is not that detailed and I can barely ...
0
votes
1answer
102 views

iptables alternative for nat in windows

When setting up a comms server I usually use iptables in linux to forward any incoming connections on a particular port to another server, e.g. Chain PREROUTING (policy ACCEPT) target prot opt ...
0
votes
0answers
135 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=*, ...
1
vote
1answer
109 views

Firewall rules using iptables using conditional statement

I have firewall rule that should accept all the connections, but drop connections from a ssh brute force attack (except 10.0.0.0/8 range). This rule will block an IP if it attempts more than 24 ...
0
votes
1answer
125 views

iptables DROP all access except my dynamic IP, is it possible and how/workaround?

If not possible, is there any workaround without affecting CPU performance? iptables -A INPUT -p tcp --dport 80 -j DROP
-1
votes
1answer
46 views

How to proxy to a web server on a node that can make outgoing connections but has no accessible IP, without root?

Not sure if this is the right StackExchange site to ask (I mainly frequent SO), but since you guys are server admin experts hopefully you'll find it relevant! Some context: I'm currently trying to ...
0
votes
1answer
71 views

Tool to allow Kerberos Authenticated users to modify Firewall settings

I run a firewall on a central router. Recently, several users want to use Skype. Since firewalling Skype virtually means to switch the firewall off, I consider to allow users to temporarily punch ...
0
votes
3answers
65 views

How do I stop someone from saturating my line & wasting CPU cycles

My web host shows inbound & outbound traffic with mrtg. I have a steady 3.5mbps inbound traffic from Nigeria. Even assuming the source IPs & destination ports are blocked with Iptables & ...
1
vote
1answer
358 views

How do I allow only certain IPSet set's to access a certain port with iptables?

I'm using IPSet to build IP ranges for different countries as follows : # Canada ipset -F ca.zone ipset -N ca.zone nethash for IP in $(wget -O - http://www.ipdeny.com/ipblocks/data/countries/ca.zone) ...
1
vote
0answers
178 views

Bypassing a transparent proxy using squid [closed]

I'm in a network where I can reach only one website for example exemple.com. Other requested web sites like google.com will be redirected to exemple.com, all other ports are work this way too ( in ...
1
vote
2answers
716 views

force LAN hosts to go through proxy

I have an IPTables firewall on a Debian server, with a bunch of hosts behind it with masquerading. In the upstream network I don't have direct access to the internet, and I need to go through a proxy ...
-3
votes
1answer
50 views

iptables allow A -> B:22 , B -> everywhere:22

I want iptables rules that let a server allow incoming ssh from a specific host and at the same time this server can connect ssh on any destination, then block any other in/out traffic Thanks in ...
0
votes
1answer
319 views

iptables Port Forwarding not working

I'm facing the problem, that my iptables rules aren't working anymore after I changed OS from Ubuntu 8.04 to Debian Squeeze. I'm trying to do a Port Forwarding by iptables -t nat -A PREROUTING -d ...
-1
votes
1answer
193 views

UFW rules for specific host / dynamic dns

How can I setup UFW (Uncomplicated Firewall) to add rules for specific hosts? Eg. I want to allow SSH only from yourpc.no-ip.org?
0
votes
0answers
128 views

APF (Advanced Policy Firewall) / iptables blocking seemingly legitimate traffic

I am running APF on my servers to handle both internal (eth0) and Internet (eth1) traffic. For the most part, everything is working correctly, but occasionally I see logs indicating that APF is ...
-1
votes
1answer
69 views

Is this CentOS 6.2 system reasonably secure as described? [closed]

This is a CentOS 6.2 system. For my login with the hosting company website, I set a 20-character mixed case, letters, numbers, symbols password and enabled two-factor authentication. In ...
1
vote
0answers
42 views

How can i manage bandwidht in linux router or firewall?

I have Linux server for internet sharing . i have 6 Mbps bandwidth, Now i want set 30Kbit to 40Kbit per user bandwidth. I want configure without proxy. It is possible that tc configration will ...
1
vote
1answer
105 views

How to ban 250.000 IP ranges?

I am using iblocklist.com and I want to ban a list of IPs I made from accessing my web server on a CentOS dedi. I have a bash script that can parse it and add the ranges one by one to iptables. My ...
0
votes
1answer
63 views

Can I put a linode instance behind our corporate firewall [closed]

I've built a little web application to collect internal survey data on a linode instance that I'd like to use in my company. My company already has windows servers set up that run intranet sites ...
0
votes
1answer
283 views

Why is UFW blocking some allowed internal connections?

My set up is this: Server 1 (192.168.1.1) - nginx (load balance) - Ubuntu 12.04 LTS Server 2 - uwsgi - Debian 7.1 Server 3 - uwsgi - Debian 7.1 UFW on server 2 and server 3, is blocking ...