Questions tagged [filtering]
The filtering tag has no usage guidance.
109
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Filtering single unrouted IP with firewall VM
I have virtualization hosts (Proxmox) running multiple VMs providing public services. I'm using a firewall appliance (OPNsense) to filter the traffic.
This works fine for a routed subnet, where the ...
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128
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How to find out if TCP connection to server is being tampered with by third-parties?
I'm under an unreliable ISP/AS, something like the GFW. They actively try to sabotage a TCP+TLS session by attacks such as sending SYN RST to established connections, making the connection timeout, ...
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138
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postfix: conditionally ignoring certain "User unknown in virtual mailbox table" errors when using a milter
Note: I originally posted this question in Unix/Linux StackExchange, but after a week, there have been no responses. I see more postfix-related discussion here, and so I've voted to close the ...
- 222
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1k
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NginX: how to rewrite response body and headers?
Context
I have a collection of static HTML pages (~10k pages) generated by some application over which I have no control. These pages are served by NginX from a location block.
Pages may contain ...
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2
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503
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Masquerade / firewalld target : impacts on filtering?
I opened a question here, but as I found some new elements, I prefer to open a new one.
Here is my situation, that can be reproduced:
Fresh Centos7 OS. Configuration of two interfaces eth1 and eth2 ...
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76
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Linux Networking - How to dynamically filter network packets within short time range
I am trying to find a solution to dynamically filter network packets with strict timing constraints and based on a IP list on a Linux Operating System
I cannot install additional software of modify ...
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578
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How to fetch the disk difference before and after adding a new disk
I'm preparing a playbook to find the newly scanned HDD from vmware, I used below filtering to fetch the no. of HDDs:
before_add: "{{ hostvars[inventory_hostname].ansible_devices.keys() | select('...
- 27
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2k
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nftables - how to log only specific type of traffic
My nftables.conf file looks like this.
#!/usr/sbin/nft -f
flush ruleset
table inet filter {
chain input {
type filter hook input priority 0;
# allow ...
- 11
1
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2
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317
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Configure Event Logger to log all or specific WPF events into specific log source and journal
I want to enable very noisy verbose WFP even for network packet audits. There will be a LOT of events and I'm curious if there is a way:
Specify a completely separate journal for them (not just ...
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1
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634
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I need to block all but one IP address from access to Mongo running on my local Mac using packet filter
Could someone help me block all incoming traffic on my network which has port forwarding set up on the router to allow incoming requests on port 27017 to be sent to the Mac running Mongo internally ...
- 101
2
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1
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688
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Saving a copy of incoming mail for specific recipient in Exim
I need to archive important mail incoming for specific address in case it gets accidentally deleted from email server, etc.
Either saving or using a pipe to archive it on backup machine is fine (I ...
- 1,391
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426
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GPO - Setting an Item-Level Filter on a Registry Collection Does not work
We're faced with a weird issue. We created a collection of Proxy Settings that we are applying to essentially everyone in the company. However we do have a subset of users that need to be excluded ...
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219
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how to only allow access to website if user access through a certain website in IIS
How can I deny access for everyone except users that originally access the site from a specific website? I use IIS 10. Does really IP/Domain filtering in IIS works for this? I tried to simulate this ...
- 111
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3k
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Display only the network interfaces which has the ip address using ip command
I use ip a to get the IP address of my machine.
Sometimes, it is getting difficult to identify when I have 20+ network interfaces.
Is there a way to display only network interfaces which has IP?
The ...
- 123
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6k
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iptables INPUT DROP NEW what effect will this have?
I'm currently working through the Linux Firewalls book and
have a set of rules setup which dictate rules to follow around every STATE except for NEW and I prefer being explicit when I'm writing code/...
- 101
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796
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Filtering and redirecting websites using dnsmasq
I've got a LAN connected to fibre router/modem for internet access, four client machines and low powered SBC running Ubuntu Server and Nginx. I'm wanting to use the SBC to filter out requests for ...
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2k
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Postfix modify email in queue and re-inject
I've a legacy webapp that sends mail to an external SMTP (specified by a conf file).
These emails came out from "noreply" account and were correctly delivered.
Now, we want mails came out from "user@...
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24
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Buisness NET - Transparent Content Filter
I am designing a network for a corporate company and would like some advice on a firewall/web filter to use that is free for HTTP and HTTPS.
The main network is gonna cost a bomb so want to use a ...
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1k
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How can it preserve source mac address unchanged after layer-3 filtering through a Linux bridge (which using bridge-utils and ebtables)
Background:
I have a Linux bridge (Ubuntu 15.10, 64bit, name Bridge B) with two physical interfaces, eth0 and eth1, and the bridge interface’s name is br0. Send A (Win 10) connects to eth0, and ...
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1k
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block website for a specific Mac address - lede firmware router [closed]
I am trying to block specific websites/urls in my home network only for specific users / Mac addresses, is this at all possible?
I have a Linksys WRT 1900 WRT v2 router running LEDE, a varient of ...
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2k
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Draytek Vigor 2820 incorrectly blocking IP address based on keyword filtering
Vigor 2820Vn router (with firmware 3.3.7.8) is blocking IP address URLs with the use of a URL keyword filter. The filter itself is working fine and blocking the URLs based on keyword, but this rule ...
- 121
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443
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Netsh trace vs PEF trace cmdlets vs NetEvent cmdlets
I am playing with capturing my network traffic and came across two different MS commandline tools that allow doing this:
a well-known netsh tool, recently equipped with powerful capture switch
a ...
- 594
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92
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Complex Postfix Filtering
I have a setup where Postfix accepts incoming and outgoing mail for my domain, then processes it through some content filters. It goes through Amavis, then SpamAssassin before going on to the user's ...
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38k
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Disabling rp_filter on one interface
I have an Ubuntu 16.04 Server which is acting as a router with multiple (VLAN) interfaces. By default, rp_filter (reverse path filtering) is enabled for all interfaces. I want to keep it that way, but ...
- 422
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1
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833
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How can I export message filters from roundcube?
We are migrating from roundcube to GSuite (Google Apps). Many of our users have set up complex filters in their roundcube account. We would like to migrate these filters to their new GSuite accounts. ...
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671
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Email server making TCP connections from source port TCP 25 to destination TCP 6666/66667
I'm hoping you guys can help shed a bit of light of what's going on here.
I have recently set up some egress filtering rules to prevent unwanted egress connections on my network. In doing so I see ...
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2
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4k
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postfix block mail to a domain only for a specific destination domain
I have a mail server that hosts many virtual domains.
The owner of one virtual domain that is on this server asked me to block mails coming from an external domain to his mailboxes.
I have this ...
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1
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324
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Azure VM Unwanted User-Agent Filtering/Blocking
I recently migrated our WP site to a Debian 8 VM running on Azure.
Since then, we are unable to process credit card payments through the RedSys payment gateway.
It seems that upon successful payment, ...
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261
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VPC router does not route traffic to CSR
I am trying to configure VPC Gateway Redundancy with Cisco Cloud Services Router (CSR).
http://www.cisco.com/c/en/us/td/docs/solutions/Hybrid_Cloud/Intercloud/CSR/AWS/CSRAWS/CSRAWS_4.html
client1---...
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1k
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IPMI only over HTTP
I am actually performing a security review for a customer and I'm being confusing about the IPMI case.
If I'm correct, the protocol is flawed by design, thus directly exposing the IPMI service (udp/...
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1
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8k
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Get Computer Object Properties for the list of servers in a file
When I run Get-ADComputer cmdlet, I can view all of the single object's properties, like below.
C:\PS>Get-ADComputer "Fabrikam-SRV1" -Properties *
AccountExpirationDate :
...
- 2,424
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102
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Postfix, ruled based filtering independently for each user
I managed to create successfully a white-list sender email filter see: here.
My goal now is to have separate filter for each user. I would like to filter out all the emails based on the rules created ...
- 121
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3
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2k
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Filter HTTPS content & enforce Captive Portal without MITM proxy
My church wants to start providing free WiFi to our guests, but with 2 requirements:
Inappropriate content (such as Pornography and Warez) must be filtered out.
The end-user must create an account ...
- 358
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1
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744
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Postfix replaces "from" when using simple filtering
I'm trying to configure Postfix (on a RHEL 6.5) to modify the content of incoming messages and forward the emails to a remote server.
I used a Perl script piped to Postfix to modify the content, and ...
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5k
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invoke filtering manually in dovecot+sieve
I've configured dovecot with a sieve filtering (also I've configured roundcube, but this does not matter I think).
It's working fine, I've set up some filters. But now I've got a huge unfiltered ...
- 237
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498
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Mailman Sender Filter RegEx not working
Does anyone have experience with sender filters using regular expressions with Mailman?
I use this regex to automatically accept all emails in the form "[email protected]" or "name.name@...
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354
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Filter outgoing mail by X-PHP-Originating-Script for Qmail
I host about 30 websites for clients on a rented server. Customers are often slow to update their Joomla and Wordpress installations. Sites get attacked quite often and I keep getting put on spam ...
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1
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150
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Drop outgoing mail to previously unavailable mailboxes in exim using mysql database
we have a larger community portal which became bigger and bigger over the years but also has some dead accounts. Recently the ip of the server was blacklisted because many mail adresses of the users ...
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1
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2k
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OpenVPN, How to filtering client
I have a problem with limiting "client" with my VPN server.
I was reading the FAQ about using iptables with disable option client-to-client, but i cannot run it.
The question is how correctly allow ...
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1
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2k
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How to setup intermediate SMTP mail server / relay to filter outgoing emails
I want to block all outgoing emails except to few whitelisted domains. what are the best ways to go about it?
Can I put an intermediate Intranet server which will do filtering based on whitelist and ...
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2
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1k
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Postfix: Filtering Outgoing Mail According to Sender Subnet
I need some specific LAN subnets to send e-mail to only my corporate domain such as printers or kiosks. How it could be possible via Postfix?
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5k
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What is the risk in turning off Base Filtering System on Windows Server...?
Let me qualify that I am a developer so I may be naive. I have a program that requires TCP communication on our local network and the box does not need to be secure. I have had some API vendors in the ...
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11k
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iptables port forwarding only for a certain range of IP
I'm using LXC containers. Each one of my containers have an ip address in 10.0.3.0/24. I want the packets that come into my host on a certain port to be redirected to a container so I use this rule:
...
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1
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3k
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How to filter RSOP to show only modified policies?
Is it possible to view only those elements of GPO that are actually modified/specified?
For example, when looking at RSOP for an OU, I have loads of options which are mostly not specified - can I ...
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3
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14k
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IIS only serve requests with hostnames
What is the optimal way to configure IIS to block direct IP access to the server? Direct IP access is only used by malicious scanners that will troll the entire internet by ip looking for vulnerable ...
- 1,434
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3
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31k
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Wireshark filtering-trying to filter out my own local ip
I'm trying to filter out my local machine's IP address 192.168.5.22.
I used ip.src != 192.168.5.22|| ip.dst !=192.168.5.22 and I keep seeing my address pop up.
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112
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How to filter email based on sender address
This is my first post to serverfault, so I hope you excuse me for asking what may seem like an obvious question. I have tried running a few Google searches, but I really don't know where to begin.
...
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949
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Postfix : intercept outgoing email by sender with amavis or custom filter?
we have some outgoing mail server with latest postfix and amavis.
I would need to intercept some outgoing email for some given senders and forward them to a "logging" account + the regular receivers.
...
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5k
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Prevent DNS responses for specific domain completely
Situation:
Server (Win 2008R2) is being used in a DNS (amplification) DDoS attack. Amplification factor is already down to 1: Set the DNS server to non-recursive and removed all root hints -> DNS ...
- 268
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577
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Squid "refusing connections" with big ACL
I've successfully set up squid and it's working as is should. I'm using "Squidman" on OS X Server (underlying squid version is 3.1.12). However, I want to use squid to block certain porn sites, so I ...
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