DHCP server with more than nine subnets on one interface

[Mana]

Hi there,

we have a specific setup where we have more than 9 different subnets and want
to activate the dhcp server in each. All those subnets are put on one interface.
This should normally work but the DHCP Server doesn’t start after a certain
amount of subnets created.
There happens an error in the dhcp_createconfig script, because the filename
is too long.
Line 64

mv shared "SN$SHARED"

Example filename:

SN_192.168.8.0M255.255.255.0_192.168.18.0M255.255.255.0_192.168.20.0M255.255.255.0_192.168.30.0M255.255.255.0_192.168.40.0M255.255.255.0_192.168.50.0M255.255.255.0_192.168.60.0M255.255.255.0_192.168.70.0M255.255.255.0_192.168.80.0M255.255.255.0_192.168.90.0M255.255.255.0_192.168.100.0M255.255.255.0_192.168.110.0M255.255.255.0_192.168.120.0M255.255.255.0_192.168.130.0M255.255.255.0

We developed two patches for this.

--- a/dhcp_configfile   2017-07-06 06:12:53.000000000 +0200

+++ b/dhcp_configfile   2017-08-02 14:30:06.464000000 +0200

@@ -141,7 +141,8 @@

SHAREDNETWORKS=`ls -d SN_* 2>/dev/null`

for H in $SHAREDNETWORKS ; do

cd $TMPSUBNETS/$H

-  echo "shared-network $H {"

+  SHAREDSUM=$(echo $H | cut -f 2 -d '_')

+  echo "shared-network SN$(cat $TMPSUBNETS/CNF_$SHAREDSUM) {"

create_subnet

echo "}"

done

--- a/dhcp_createconfig 2017-07-06 06:12:53.000000000 +0200

+++ b/dhcp_createconfig 2017-08-02 14:30:18.576000000 +0200

@@ -61,7 +61,9 @@

done

done

if ! [ -z "$SHARED" ] ; then

-          mv shared "SN$SHARED"

+           SHAREDSUM="$(shasum <<< $SHARED | cut -f 1 -d ' ')"

+           echo -n $SHARED > CNF_$SHAREDSUM

+           mv shared "SN_$SHAREDSUM"

fi

fi

fi

This creates a fixed name length file and adds the config string otherwise set
as the filename to another file.
We hope this helps with findig the issue and probably fixing it.

[tuxad]

in the fix decription is a small mistake:

This creates a fixed name length file and adds the config string otherwise set
as the filename to another file.

This creates a fixed name length directory and adds the config string otherwise set as the directory name to another file.

This is my training because I released the error description.

[Author]

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