Menu
What's new
By:
Filters Better Search

Dnsmasq configuration

  • SNBForums Code of Conduct

    SNBForums is a community for everyone, no matter what their level of experience.

    Please be tolerant and patient of others, especially newcomers. We are all here to share and learn!

    The rules are simple: Be patient, be nice, be helpful or be gone!

D

Denna

Senior Member
1) Is it possible to view the configuration of dnsmasq after /jffs/scripts/dnsmasq.postconf runs ?

2) What is wrong with the following dnsmasq.postconf script ? Running this script from the command line returns ...
Code: 
./dnsmasq.postconf: line 9: : No such file or directory
Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.1 eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(3 2 1 0)
VLAN_ID=(10 20 30 40)

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
   cat <<EOF >>"$1"
   interface=${PRIV_VLAN[i]}
   dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
   dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
   dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
   EOF
done
 
Last edited:
Denna said:
1) Is it possible to view the configuration of dnsmasq ?

2) What is wrong with the following dnsmasq.postconf script ? Running this script from the command line returns ...
Code: 
./dnsmasq.postconf: line 9: : No such file or directory
Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.1 eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(3 2 1 0)
VLAN_ID=(10 20 30 40)

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
   cat <<EOF >>"$1"
   interface=${PRIV_VLAN[i]}
   dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
   dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
   dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
   EOF
done
Click to expand...
1) Yes in /etc/dnsmasq.conf
2) Have you marked it as executable +x?

Usually postconf isn't run manually, rather it is called when the dnsmasq service restarts
Code: 
service restart_dnsmasq
 
I was running it to determine if there were any issues with the for loop.
 
Denna said:
2) What is wrong with the following dnsmasq.postconf script ? Running this script from the command line returns ...
Click to expand...
For starters, unless bash is installed through Entware on your router, use sh instead of bash in the shebang:
Code: 
#!/opt/bin/sh
Then, $1 is not defined in your script, add it with the following so the script knows what file to edit:
Code: 
CONFIG=$1
source /usr/sbin/helper.sh
This is required for a *.postconf script as per the wiki.
Then replace the $1 with $CONFIG in your code.
 
@thelonelycoder,

I'm using bash due to the use of an array.

The same error is now occurring on line 10.
Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG=$1
source /usr/sbin/helper.sh

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
   cat <<EOF >>"$1"
   interface=${PRIV_VLAN[i]}
   dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
   dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
   dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
   EOF
done
 
Denna said:
@thelonelycoder,

I'm using bash due to the use of an array.

The same error is now occurring on line 10.
Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG=$1
source /usr/sbin/helper.sh

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
   cat <<EOF >>"$1"
   interface=${PRIV_VLAN[i]}
   dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
   dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
   dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
   EOF
done
Click to expand...
I see, try to outdent the EOF, maybe that helps:
Code: 
 #!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG=$1
source /usr/sbin/helper.sh

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
   cat <<EOF >>"$CONFIG"
interface=${PRIV_VLAN[i]}
dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
EOF
done
 
<sigh>

Are you actually passing the parameter into your script?

./dnsmasq.postconf /etc/dnsmasq.conf
 
Figured it out.

Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG=/etc/dnsmasq.conf

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
cat <<EOF >>"$CONFIG"
interface=${PRIV_VLAN[i]}
dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
EOF
done
 
Denna said:
Figured it out.

Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG=/etc/dnsmasq.conf

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
cat <<EOF >>"$CONFIG"
interface=${PRIV_VLAN[i]}
dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
EOF
done
Click to expand...
That's because you hardcoded the reference to the config file rather than pass it as an argument, as per @ColinTaylor

Whatever works I guess
 
From the command line, running "/jffs/scripts/dnsmasq.postconf /etc/dnsmasq.conf" does update the /etc/dnsmasq.conf file.

Code: 
#!/opt/bin/bash

PRIV_VLAN=(eth1.2 eth1.3 eth1.4)
SWITCH_PORT=(2 1 0)
VLAN_ID=(20 30 40)
CONFIG="$1"

for (( i=0; i<${#PRIV_VLAN[@]}; i++ )); do
cat <<EOF >>"$CONFIG"
interface=${PRIV_VLAN[i]}
dhcp-range=${PRIV_VLAN[i]},192.168.${VLAN_ID[i]}.0.2,192.168.${VLAN_ID[i]}0.254,255.255.255.0,8h
dhcp-option=${PRIV_VLAN[i]},3,192.168.${VLAN_ID[i]}.1
dhcp-option=${PRIV_VLAN[i]},6,208.67.222.222,208.67.220.220
EOF
done

However, when dnsmasq.postconf is run at bootup, the changes are not visible in "/etc/dnsmasq.conf".
 
Denna said:
... However, when dnsmasq.postconf is run at bootup, the changes are not visible in "/etc/dnsmasq.conf".
Click to expand...
I think you could do this entirely with Ash script (the default shell script: /bin/sh). The firmware would be the only dependency, no Entware-ng in this case.

If you ever need functionality not available in Ash shell, try adding Awk script (/usr/bin/awk). See this example for how I used Awk to implement some script functions. This is just an example for how one could extend the default shell with Awk scripts. You don't actually need Awk for your Dnsmasq auto-configuration because what you're trying to do is very easy.
https://www.snbforums.com/threads/block-specific-ip-using-iptables.37614/#post-342983
 
Denna said:
@ColinTaylor,

What do you mean "for once" ?​
Click to expand...

Whilst it is very useful/flexible to be able to use scripting to modify configs via the .postconf method, since the VLAN configurations are known in advance, why not simply hard-code your required three VLANs in /jffs/configs/dnsmasq.conf.add thereby removing any Entware dependencies? (and totally eliminates possible scripting logic failures!;) )
 
Last edited:
@Martineau, @Fitz Mutch and @Jack Yaz,

Thanks to @Jack Yaz for pointing out the bash/Entware delay.

Replaced bash with sh.

@Martineau - I didn't want to hardcode any information so the script could remain flexible by changing environmental variables in one place. The variables are used by more than one script.

@Fitz Mutch - Thanks for the awk option suggestion.
 
Last edited:
You must log in or register to reply here.

Similar threads

N
RT-AX86U-Pro, WAN disconnect every 36 hours
2
Replies
25
Views
2K
Nick24
N
MegaMango
dnsmasq-surrogate for RT-BE88U: Ad Blocking & Security Enhancement
Replies
2
Views
570
MegaMango
MegaMango
W
RT-AX86U with latest version 3004.388.8_2 always crash and reboot
2
Replies
37
Views
4K
laxdog
laxdog
drinkingbird
Odd interaction of dnsmasq DHCP and NVRAM
Replies
1
Views
1K
eightiescalling
E
GraniteStateColin
DNSmasq to provide DHCP IP # and DNS name for systems on LAN
Replies
19
Views
3K
Patrick9876
P
Similar threads
Thread starter Title Forum Replies Date
C Does default dnsmasq configuration store LAN names? Asuswrt-Merlin 6
S Solved New ISP - WAN Setup - Will not work with custom WAN DNS - dnsmasq.conf Asuswrt-Merlin 1
B dnsmasq: failed to create listening socket for 192.168.1.1: Address already in use Asuswrt-Merlin 7
Siff Setting dnsmasq on Asuswrt-Merlin Asuswrt-Merlin 8
V Import lease list to dnsmasq.conf.add Asuswrt-Merlin 5
V dnsmasq.config.add without ip? Asuswrt-Merlin 2
XxUnkn0wnxX Proper dnsmasq config for local resolver? Asuswrt-Merlin 3
saison2023 Any way to diagnose further these dnsmasq restart events? Asuswrt-Merlin 5
P In dnsmasq, how do I stop overriding an address if the server goes down? Asuswrt-Merlin 1
P dnsmasq custom domain doesn't work on windows 10 Asuswrt-Merlin 1

Similar threads

Latest threads

Support SNBForums w/ Amazon

If you'd like to support SNBForums, just use this link and buy anything on Amazon. Thanks!

Sign Up For SNBForums Daily Digest

Get an update of what's new every day delivered to your mailbox. Sign up here!

Members online

Total: 846 (members: 29, guests: 817)
Top