Custom Script event for new LAN/WLAN clients (dhcp)?

[Stefan1200]

I saw in the documentation that a user script for an dhcpc-event is possible. But the documentation talks about DHCP events on the WAN interface. Is there something related for LAN/WLAN clients, or did I misunderstand the documentation?

I want to create something like a user script, which sends me a mail that a new DHCP client was connected to my LAN, maybe with information like IP address and more, if possible.

 

[sbsnb]

This may be of some use:

https://jpmens.net/2013/10/21/tracking-dhcp-leases-with-dnsmasq/

 

[ColinTaylor]

You would normally create a dnsmasq.conf.add file which contains a dhcp-script= command. However, Asus appears to have made a change regarding this. Read this post by RMerlin:

https://www.snbforums.com/threads/r...-9-is-now-available.54843/page-15#post-465039

So check your current dnsmasq.conf file to see if it already contains the dhcp-script= command.

 

[EmeraldDeer]

I suppose logging as a DHCP client (WAN) is plausible, but it makes more sense in the context of a DHCP server (LAN), which is what dhcp-script does.

In my case, a "dhcp-script=" definition had not already been defined in /etc/dnsmasq.conf

# cat /jffs/scripts/dnsmasq.postconf
#!/bin/sh
CONFIG=$1
source /usr/sbin/helper.sh
pc_append "dhcp-host=00:24:e4:5f:00:00,192.168.66.110,Therm" $CONFIG
pc_append "dhcp-host=00:24:e4:5c:00:00,192.168.66.111,Scale" $CONFIG
pc_delete "dhcp-option=dnsf5" $CONFIG
pc_delete "dhcp-option=dnsf6" $CONFIG
pc_append "dhcp-script=/jffs/scripts/log-dhcp.sh" $CONFIG
pc_append "neg-ttl=3600" $CONFIG
pc_delete "no-negcache" $CONFIG
pc_delete "servers-file=/tmp/resolv.dnsmasq" $CONFIG
#
. /opt/share/diversion/file/post-conf.div # Added by Diversion

I only wanted DHCP events to be logged by the syslog daemon.

# cat /jffs/scripts/log-dhcp.sh
#!/bin/sh
myscriptname=$(/usr/bin/basename $0)
/usr/bin/logger -t ${myscriptname} -p local6.info "Action $1, MAC $2, IP_address $3, Hostname $4"

 

[EmeraldDeer]

If your router already has a "dhcp-script=" definition in /etc/dnsmasq.conf, then

• Use pc_replace instead of pc_append
• At the end of your script call whatever the existing dhcp-script had been calling

 

[Stefan1200]

Thanks for all your hints, I will check this out soon.