All Questions
92
questions
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28
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Many UFW BLOCKs pr minute from numerous ports and numerous IP addresses
My syslog is flooded with numerous attacks of some sort coming from multiple sources.
I looked at all the other references in the search feature but none addressed tcp and from numerous sources
Feb 16 ...
- 207
0
votes
0
answers
84
views
Enable journalctl within Ubuntu container
I've got an Ubuntu 22.04 container running on a MacOS host. Inside the container, I'm fiddling with routing and would like to add some -j LOG rules to iptables to see where my packets are going. ...
- 821
1
vote
1
answer
262
views
MAC address rewriting using tc
I am using tc to change the MAC address of incoming packets on a TAP interface (tap0) as follows where mac_org is the MAC address of a guest in a QEMU virtual machine and mac_new is a different MAC ...
- 13
0
votes
0
answers
22
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ipset add white_list_net_port 128.0.0.0/1,udp:443-444 error
ipset v7.1, protocol version: 7 When I execute 'ipset add white_list_net_port 128.0.0.0/1,udp:443-444', the system reports 'ipset v7.1: Hash is full, cannot add more elements',white_list_net_port is ...
- 1
2
votes
2
answers
908
views
nftables deleting a rule without passing handle (similar to iptables delete)
iptables syntax for delete is much simpler. if we replace the "append" with delete we get command for deletion of the rule.
nftable provides similar construct for few rule management aspect ...
1
vote
1
answer
190
views
Why does it go through netfilter postrouting when visiting local ports?
Environment：
[root@VM-32-4-centos ~]# uname -r
3.10.0-514.26.2.el7.x86_64
I have set log printing in the following chain：
[root@VM-32-4-centos ~]# iptables -A INPUT -p tcp --dport 8000 -j LOG --log-...
- 11
3
votes
1
answer
775
views
In addition to `ip rule`, `ip route`, `iptables`, is there anything else that could affect routing and packet filtering in linux?
Recently I'd like to set CF WARP client on my VPS, but encountered a strange problem. I’m not sure if this is the right place to ask this question, if not I’m very sorry and delete it.
Background:
I ...
- 153
1
vote
1
answer
723
views
routing table configured with "ip route" part of the "iptables"?
This question is frequent and has already a lot of answers, but I still don't get it. Is the routing configured with "ip route add .." part of the iptables flow? Is the "routing ...
- 83
0
votes
1
answer
812
views
netfilter: ipset vs iptables recent module
what exactly are the practical differences between iptables recent module and ipset ?
I know recent module only allows IPs, whereas ipset allows subnets. But other than this, what is the main ...
- 568
0
votes
1
answer
35
views
Why didn't iptables apply the sames rules?
For some reason, my network encountered "Destination unreachable no route" error, this error happened periodicly, later I found that was a bug of my program.
But during that time, I found a ...
- 53
0
votes
0
answers
158
views
Forward Traffic to virtual box (Genymotion)
I am running an Android virtual machine (Samsung Galaxy S10 & android 10.0 API29) using Genymotion. I have a VPN running there (OpenVPN protocol). Now I am running all this over my Debian based ...
1
vote
2
answers
2k
views
During the lifecycle of "iptables", in which step, will kernel take advantage of "route table"?
iptables. I have went though the manual of Iptables and known some basic concepts, e.g. chain, table, hook, rule and targets. In the Linux ecosystem, iptables is a widely used firewall tool that ...
- 194
0
votes
1
answer
401
views
Netfilter: in which situation, NF_IP_FORWARD will be triggered?
Netfilter Hook: NF_IP_FORWARD
There are five netfilter hooks that programs can register with. As packets progress through the stack, they will trigger the kernel modules that have registered with ...
- 194
1
vote
1
answer
2k
views
which layer does Netfilter and IPTables works on in the OSI model?
IPTables are the basic and very commonly used firewall in Linux systems. netfilter provides 5 hooks that programs can register with.
which layer does Netfilter and IPTables works on?
IP Packet level
...
- 194
0
votes
1
answer
553
views
How can I filter a packet after an iptables MASQUERADE?
I am trying to build a multi-WAN router based on Debian Buster (kernel version 4.19). It has multiple 'LAN-side' network interfaces (e.g. lan0, lan1, ... lanM), and also multiple 'WAN-side' interfaces ...
- 101