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linux_router:nftables_control [2020-06-27 Sat wk26 11:18] – [NFTables IP Control] baumkplinux_router:nftables_control [2023-04-30 Sun wk17 17:43] (current) – external edit 127.0.0.1
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- +{{tag>linux nft nftables nmap}} 
-=====NFTables IP Control=====+ =====NFTables IP Control=====
 I primarily set this feature up to act as a form of parental control on my home internet access.   I primarily set this feature up to act as a form of parental control on my home internet access.  
  
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 ''crontab'' is finicky! crontab does not necessary use BASH and the full path to the command must be given for reliable performance. Further to this cron error messages are sent to the system mail server, so if this is not setup or otherwise not working the error message go nowhere.   Systemd has a service to redirect output of cron jobs to systemd's journal: ''/usr/bin/systemd-cat -t controllist'', again the full path is given.  The command path can be found using ''which'', e.g. ''which nft''.  In any case the final crontab command entry would look like: ''/usr/bin/systemd-cat -t controllist /home/baumkp/controllist.sh'', remembering everything after the 5th space is passed to the system shell command interpreter. ''crontab'' is finicky! crontab does not necessary use BASH and the full path to the command must be given for reliable performance. Further to this cron error messages are sent to the system mail server, so if this is not setup or otherwise not working the error message go nowhere.   Systemd has a service to redirect output of cron jobs to systemd's journal: ''/usr/bin/systemd-cat -t controllist'', again the full path is given.  The command path can be found using ''which'', e.g. ''which nft''.  In any case the final crontab command entry would look like: ''/usr/bin/systemd-cat -t controllist /home/baumkp/controllist.sh'', remembering everything after the 5th space is passed to the system shell command interpreter.
  
-====Limit Rate on IP Adress Range==== +++++ example: ''sudo crontab -e'' | 
-''sudo nft add rule inet firewall forward handle 29 iifname "ppp1" ip daddr { 192.168.1.100-192.168.1.253 } limit rate 1200kbytes/second burst 9000kbytes counter accept''+<code> 
 +# Edit this file to introduce tasks to be run by cron.  
 +#   
 +# Each task to run has to be defined through a single line  
 +# indicating with different fields when the task will be run  
 +# and what command to run for the task  
 +#   
 +# To define the time you can provide concrete values for  
 +# minute (m), hour (h), day of month (dom), month (mon),  
 +# and day of week (dow) or use '*' in these fields (for 'any').  
 +#   
 +# Notice that tasks will be started based on the cron's system  
 +# daemon's notion of time and timezones.  
 +#   
 +# Output of the crontab jobs (including errors) is sent through  
 +# email to the user the crontab file belongs to (unless redirected).  
 +#   
 +# For example, you can run a backup of all your user accounts  
 +# at 5 a.m every week with:  
 +# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/  
 +#   
 +# For more information see the manual pages of crontab(5) and cron(8)  
 +#   
 +# m h  dom mon dow   command  
 +# Example of job definition:  
 +# .---------------- minute (0 - 59)  
 +# |  .------------- hour (0 - 23)  
 +# |  |  .---------- day of month (1 - 31)  
 +# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...  
 +# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat,sun  
 +# |  |  |  |  |  
 +# *  *  *  *  *   user-name command to be executed  
 +# 45 23 *  *  *   /usr/bin/systemd-cat -t controllist /home/baumkp/controllist.sh 5h15m  
 +# 30 23 *  *  5-6 /usr/bin/systemd-cat -t controllist /home/baumkp/controllist.sh 5h30m  
 +# 30 22 *  *  0-4 /usr/bin/systemd-cat -t controllist /home/baumkp/controllist.sh 6h30m 
 +</code> ++++ 
 + 
 +The crontab files are stored at ''/var/spool/cron/crontabs/$USER''.  You should not edit these files directly, use ''crontab -e'' for current user or ''sudo crontab -e'' for root. 
 + 
 +====Limit Rate on IP Address Range==== 
 +The rate limit command needs to be placed before the other commands that could accept packets before reaching the rate limit command, e.g. ''ct state established, related counter accept''.  The following command will add the command at handle 29: 
 +  *''sudo nft add rule inet firewall forward handle 29 iifname ppp1 ip daddr { 192.168.1.100-192.168.1.253 } limit rate 1200kbytes/second burst 4000kbytes counter accept'' 
 +The existing rules with handles displayed can be displayed with:  
 +  *''sudo nft list table inet firewall -a''  
 +The above command will accept packets according to filter that do not exceed 1200kbytes/second with a burst of 9000kbytes. 
 +Another form of syntax would be to drop packets that exceed the limit, this allows the amount of drop packets to be seen with the counter enabled:  
 +  *''sudo nft add rule inet firewall forward handle 29 iifname ppp1 ip daddr { 192.168.1.100-192.168.1.253 } limit rate over 1200kbytes/second burst 4000kbytes counter drop'' 
 + 
 +My internet bandwidth is currently limited to about 25Mbit/s, dividing by 8 give approximate MByte/s, i.e. about 3MB/s or 3000mbytes/s or 3000kbytes/s, hence I limit the kids bandwidth to 1200kbytes/s with an allowed burst of 4000kbytes.
 ====Some other tools==== ====Some other tools====
   *''sudo nmap -sn 192.168.1.0/24''   *''sudo nmap -sn 192.168.1.0/24''