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Questions tagged [block]

135 questions
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firewall-cmd block outgoing connection to an ip list

I have searched a lot about this, this is possible to have many of these commands one for each ip: /usr/bin/firewall-cmd --direct --add-rule ipv4 filter OUTPUT 0 -d ::FFFF:85.185.0.0/112 -j REJECT /usr/bin/firewall-cmd --direct --add-rule ipv4…
Steve Moretz
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Block windows 10 updates (off the computer)

I have a Windows 10 computer that is running software that I cannot service'ize. My problem is that I have followed every known process for disabling, discontinuing, or stopping Windows from auto updating/rebooting. None of them actually work. I've…
userxsw2zaq1
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How can I stop this kind of exim attack?

I has been search here, BUT no topic about my question (they just ask for their email was rejcted, but this time, not my email was been reject), it seem someone try to send spam out via my server, however this one is very annoying, it start to try…
simonlo
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iptables: How to block UDP between devices on LAN-side of gateway (using dd-wrt firmware)

Goal: To block UDP traffic to devices on LAN-side of this gateway (using dd-wrt firmware), that communicate with internet and each other, to test specific communications applications running on each device. Exceptions: allow the bare minimum UDP…
Grumpy Curmudgeon
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How do I figure out what prevents incoming connections on a certain port?

I would like to enable SSH connections on an additional port on my machine, for reasons. It is a physical machine (not a VM), running Devuan GNU/Linux Chimaera (~= Debian 11.0 without systemd). The default SSH server (OpenSSH_8.4p1 Debian-5, OpenSSL…
einpoklum
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ban `./ANY/IN` DNS queries using iptables

I am getting some denied DNS queries I'd like to ban using iptables, to avoid bind to send augmented replies to the server ... and that they're simply annoying in my logs. (.): query (cache) './ANY/IN' denied I know that, with queries…
Avenger
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Bind/Fail2ban how to reject requests from certain domain

Today I got my VPS stucked. Centos 7, 4 cores, Bind 9.11. From ssh I got Message from syslogd@host at Jul 18 09:46:16 ... kernel:NMI watchdog: BUG: soft lockup - CPU#0 stuck for 41s! [f2b/observer:1299] From another ssh screen leaving top running…
Daniel Franco
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Fail2ban with Firewalld on RHEL 8 - Fail2ban seemingly blocks IPs, but they are not really blocked

I'm running fail2ban on RHEL 8 using firewalld. According to the fail2ban log (with DEBUG level) it blocks IP addresses without any error, but in fact there are no such rules in firewalld and nftables. In the jail.local config file I have set…
user766753
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How to restrict users switching from su command

How can I restrict users switching by su command? Suppose there are 3 users (root,user1 and user2) only root and user1 can switch by using su command. root or user1 should not be able to switch to user2 by using su command. root@instance# su - user1…
Prabath Lasantha
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I cant block ACK packets going through port 80

I want to block nmap's ack ping probes and in order to do that, I fist need to block all incoming ack packets coming on port 80. I used this command but it didnt work: iptables -A INPUT -p tcp --dport 80 --tcp-falgs ALL ACK -j DROP The thing is it…
xparks37
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How should I block traffic to destination port using iptables?

I have received an abuse from my server provider and one thing which is the same is that the target on destination IPs is the SMB (445) port . How can I block destination traffic to port 445 using iptables? >…
Mr Pro
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Can nginx block ~20000 ips?

Can nginx block ~20.000 ips? And should i block ips (https://lists.blocklist.de/lists/all.txt) with nginx?
Nguyen Tien Huy
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Is there a way to block internet access using iptables for particular access points

In our company we have several access points. For some of them in the production area it should be disallowed to use them for accessing the internet. The router we have has (at least) two interfaces: one for the local traffic (intif) and one for…
code-chicken
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Block a computer from all but 1 or 2 websites?

I'm setting up a computer for our machine shop that is intended for them to only get to a couple sites they may need while working. It needs to still be on our network so they can look at files saved on the network, but it shouldn't be able to get…
Uncle Bajubjubs
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How to prevent an openly recursive DNS server from being abused for DNS amplification

I have a business need to provide an open and recursive DNS. This DNS has of course been heavily abused by DNS amplification attacks, resulting in 5-10 Mbps sustained outbound load only caused by spoofed ANY requests. I thus had to find a solution…
John
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