A Firewall is an application or hardware device used to inspect and filter network traffic.

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199 views

Need help understanding capturing from Wireshark?

I am having issues with my FTP servers. Connecting, sending and receiving fail sometimes, and it is not consistent. I manage to capture and filter by IP the packets, I just need pointers on what can ...
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1answer
91 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 ...
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1answer
5k views

PPTP connection fails with errors 800/806

I've got a client (Server 2008 R2) that won't connect to our production environment PPTP VPN server (Server 2003, running RRAS). The server is behind a firewall that has TCP1723 open as well as GRE. ...
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1answer
675 views

cisco asa reloading

After having both memory and code upgrades, we have a significant number of our asa 5520's (in active/standby pairs) develop problems. The problem manifests itself as losing connectivity to the other ...
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1answer
77 views

Allow only one ipaddress through a cisco firewall without pcs knowing there is a proxy server

We have a PC behind a firewall. (ASA 5505) [PC] => [ASA Firewall] => [Corporate Proxy/Firewall/Anything] => [Internet] :- where the PC and ASA Firewall are under our control... and the rest are ...
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1answer
114 views

How to provide access to lan mysql DB from a remote server?

Consider the below network configuration: A client connects with its workstation to the application server on the Web. The application is full HTML, so only browsing through HTTPS is enough to ...
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1answer
109 views

Domain based firewall outbound rules

We have a webserver (IIS) hosting some e-commerce websites. Our firewall in front of the server has a restriction on inbound and outbound traffic. The webserver makes outbound calls to payment ...
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1answer
139 views

Cannot directly reject traffic on port 25

My server is running Ubuntu 10.04.4 LTS and I want to reject traffic to port 25. The goal is this: $ telnet {ip} 25 Trying {ip}... telnet: connect to address {ip}: Connection refused telnet: Unable ...
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1answer
79 views

postfix stops accepting connections from certain IPs

I had postfix up and running, and I think it was complete, although there was still a little testing to do. But at some point, it stopped accepting connections from my home computer. I tried to telnet ...
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1answer
487 views

Packets marked INVALID in FORWARD rule

I have a firewall that has 3 IP aliases on 1 physical interface. Packets get dropped between these 3 interfaces (either ICMP, HTTP, or anything else). We tracked it down to these packets being marked ...
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48 views

Assign VPN users to Domain Network

How can I assign VPN users (provided using NPS) to the Domain Network in firewall/network center settings? Currently connection occurs only when I assign a particular rule to the Public network ...
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1answer
301 views

IPTables unable to nat trough VPN

I have a VPN connection to a server on a remote location. I want other pc's to be able to reach the webserver on the remote location trough the VPN connector. But i can't get where i want. This is ...
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1answer
277 views

Rackspace Firewall/Gateway Setup

I have rackspace account and wish to have this sort of setup: Firewall/Gateway eth0 - Public IP (56.X.X.X) eth1 - Private IP (10.X.X.X) Ubuntu 10.10. Accepts connections from the internet and ...
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1answer
2k views

Watchguard config, drop-in or mixed-routing mode?

I have a Watchguard XTM 2 that is currently acting as a firewall and a router for my business network, I currently have the WG setup in mixed-routing mode and am happy with the current configuration. ...
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1answer
59 views

Is there any danger in disabling windows firewall on a azure worker role?

I'm trying to troubleshoot a bug on our Azure worker role where we occasionally get the error "Unable to read data from the transport connection: An established connection was aborted by the software ...
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1answer
58 views

Websever behind Sonicwall, Gateway Timeout

I am stuck here, I have a Cradlepoint CBA750B in IP-passthrough mode connected to x1 on my Sonicwall NSA220. Behind the Sonicwall I have a webserver on the LAN. I have X1 set to use DHCP to get the ...
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1answer
292 views

How to make an existing caching Nginx proxy use another proxy to bypass a firewall?

My question is about using Nginx as a proxy behind another proxy. (Somewhat confusing.) I want to set up Nginx so it acts as a caching proxy server to an npm mirror. Here is the link: ...
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1answer
181 views

Iptables configure gateway virtual machine with 2 interfaces

I have a virtual machine that works like a gateway from other virtual machines. The configuration of the interfaces is the following UBUNTU: eth0: ip: 10.0.2.2 netmask 255.255.255.255 ...
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1answer
110 views

Automatically ask router for port redirection on ubuntu

Is there a way to use uPnp or something to automatically ask a router/firewall to redirect data coming from outside to a machine running ubuntu? Here's the deal, I'm supposed to prepare a certain ...
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1answer
290 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 ...
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1answer
134 views

Limit ftp connections with pf firewall at FreeBSD

I want to limit simultaneous FTP connections to my FreeBSD server with the pf firewall. For example that only 10 simultaneous connection are possible to the port 20 or 21 from one source IP. I use ...
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1answer
521 views

Should I create a second WAN Interface for a new SSLVPN setup on my Sonicwall 2400?

Sonic Wall 2400 I'm setting up a new SSLVPN on our Sonicwall, very new to this. I currently have an exchange server as well, so mail.company.com is directed to our mail server. I'd like to setup a ...
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1answer
58 views

Outbound ports for a firewall for webserver and db server

I have an environment where there is one firewall, and there is a secure segment and a DMZ segment behind it. There is a bunch of servers in the secure segment - DB server, the QA server, etc and ...
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1answer
1k views

Juniper SSG5 DHCP IP Pool is full. Unable to offer IP address to client

hope we have some Juniper guys around, I have configured a Juniper SSG5 as our main firewall/router the DHCP server set on interface bgroup1 to have a rang from 10.10.10.76 to 10.10.10.210 All ...
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1answer
124 views

How to filter TCP packets based on flags using Packet Filter

Well, I didn't know exactly how to ask this question, but I know that you can use the keyword flags to especify which flags you want to filter. According to the documentation of the Packet filter: ...
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1answer
360 views

How to find which local process is sending spam on a Windows Server 2008 server

I am managing a Win Server 2008 system with a number of hosted web sites. Recently I found that something was sending spam through our SMTP server. The logs indicate that the connections were being ...
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1answer
176 views

Configuring a firewall appliance with 2 VLANs - how are the outbound links on the firewall configured?

We just ordered a sonicwall NSA 4500 firewall and I am preparing a network diagram for its arrival. We have 12 servers in a newly setup rack, a 48-port switch, and a Sonicwall NSA 4500 firewall I ...
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1answer
2k views

Redirect private LAN traffic to internal server when DNS answers with external IP

I have a mikrotik RB2011 router/firewall. Inside the firewall I have a web server that has an private IP (lets say it's 192.168.1.5) On the WAN side of the firewall I have a static IP (assume it's ...
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1answer
452 views

Dropping incoming requests for a specific file with iptables

Server is a standard LAMP stack configured via cpanel on CentOS 5.9. We have one file, call it bad.php, on one of our domains that is mistakenly being accessed about 10 times a second by a service ...
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1answer
530 views

Per-user dynamic traffic shaping

At work we have a dedicated Internet link for everyday use (servers use a different link) with limited upload bandwidth (currently 3Mbps). Since there are ~80 users, sometimes this upstream link ...
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1answer
447 views

pfsense firewall filter rules behind nat?

i am new in pfsense i have vmware which pfsense and windows xp are installed on them pfsense in using ip 192.168.44.1 for LAN and 192.168.121.129 for wan (which is NAT) my win xp ip is 192.168.44.2 ...
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1answer
174 views

Dual Cisco ASA 5505 passing RSTP in transparent mode

I'm looking at moving to colocation and one area being discussed is networking redundancy. I can get a dual feed from a two different datacentre switches configured with Rapid Spanning Tree Protocol ...
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1answer
186 views

Finding spoofed IP address on network

I have a few IP spoof dropped messages coming out of my Sonicwall firewall, we'll call them Source A and Source B. Both of these sources have the same mac address indicating they're coming from the ...
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1answer
80 views

NAT ports - how do they work?

I have the following network schema: Computer A: three nics: NIC 1 (eth0): dhcp, public internet NIC 2 (eth1): static 192.168.1.1, gateway for Computer B NIC 3 (eth2): static 192.168.2.1, gateway ...
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1answer
330 views

AWS EC2 security group source

I'm currently trying to configure a security group and allow MS SQL connections from my other instance. I want to be able to specify the security group's name as the source. But the connection is not ...
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1answer
825 views

Ubuntu 12.04 open port 80 inside WLAN

I have an nginx server running on ubuntu 12.04 that serves http through port 80 and https through port 443. Everything works fine if I access it from the same computer via localhost, 127.0.0.1 or the ...
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1answer
266 views

Programatically blocking a url to rate limit, unblocking or expiring the block

My requirements are to be able to rate limit or temporarily hard block any requests to our server for a particular URL if the client sends more than x requests per hour. There are about 250K urls ...
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1answer
4k views

Handshake violation when trying to access one website

I have a TZ 190 Wireless Enhanced with SonicOS Enhanced 4.2.1.0-20e. Yesterday, people could access without any problems a bank website wich uses HTTPS. Today, it is imposible to access only that ...
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1answer
748 views

Amazon EC2 Socket connection not being accepted

I am trying to run a java application on my EC2 instance. The application accepts socket connections on port 54321. If I try and connect to it, it times out. My Security Group is set as: TCP Port ...
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1answer
346 views

APF - allow_hosts.rules - Port Ranges [error]

I am running into a problem trying to specify that webmin can only be accessed from my private IP. But I can get the port ranges to correctly work. I am using this in the allow_hosts.rules file. ...
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1answer
367 views

How to secure a Windows SBS Server against fraudulant login attempts?

I administer a Windows Small Business Server 2003 R2 server for a small business. The only ports that this server has exposed to the internet are SSL and the RDP tunnelling port used by the SBS remote ...
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1answer
130 views

Firewall management in Windows Web Server 2008

I've been trying for hours to block a single port(sql server) from remote access. In linux a single line of iptables command would be enough. In 2008 i couldn't manage to make it happen. The ...
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1answer
312 views

How can Rackspace cloud servers be set up with an EC2 type approach to firewalls?

I'm looking at using Rackspace cloud servers for some Windows based web hosting, and having used Amazon EC2 for similar projects before, I was disappointed to find Rackspace don't employ the EC2 ...
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35 views

Loading wordpress admin page prevents and blocks further requests

I've installed a Wordpress site on a host (actually I moved it from localhost). The site loads and works perfectly, however if I log in with Admin, the admin page doesn't completely load and all ...
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80 views

Remote Destkop into Server 2008R2 with Firewall On

I've got a fresh install of Remove Server 2008 R2, 64 bit. The problem is I can't Remote Destkop into it. I clicked 'Enable Remote Desktop' inside 'Initial Configuration Tasks', and set it to: ...
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498 views

Setup Single NIC DC RRAS with Firewall

I have a single NIC DC server set up for a few local client machines to mainly serve Files and provide a consistent computing environment across local client workstations thru Folder Redirection. ...
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226 views

Ubuntu and uwf - ERROR: '/lib/ufw/user.rules' is not writable

Every time I try and update a rule I get this error. # sudo ufw allow from 111.111.111.111 sudo: unable to resolve host myserver ERROR: '/lib/ufw/user.rules' is not writable How do I resolve?
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908 views

MIKROTIK: Open port 110

I have a mikrotik web proxy with firewall and hotspot. I'm able to open major part of TCP (e.g. 25) port but not the port 110 for TCP. What is the difference? How can I open the port on firewall ...
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48 views

Regression testing for firewall changes

We have a number of firewalls in place around our organisation and in some cases packets can pass through four levels of firewall limiting the flow TCP traffic. A concept that I'm used to from ...
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620 views

Best way to bridge two networks protected by Endian firewalls

We are being forced to move our servers from one rack in the data center to another - and will have access to our Internet IP block live in both racks. I want to be able to power down a server, move ...