bug in DHCPv6 option parse for on commit {} ?

perl-list perl-list at network1.net
Thu Dec 22 15:41:30 UTC 2016

having something like this in the dhcpd.conf file for DHCPv6: 

on commit { 

if exists dhcp6.ia-na { 


concat( "LEASED,", 

"IPTIME,",binary-to-ascii(10, 32, "", substring(option dhcp6.ia-na,36,4)),"," 




Will produce a value for IPTIME that is equal to the time requested by the client instead of what was given by the server. 

For example: 

Client (Redhat Enterprise Linux 7 - ISC DHCP 4.2.5) sends a Renew for an IPv6 address via DHCPv6 requesting the following times (As seen in wireshark capture): 

T1: 3600 
T2: 5400 
Preferred Lifetime: 7200 
Valid Lifetime: 7500 

Server (generic Linux - ISC DHCP 4.3.3) is configured with this time setting in the pool6 {} statement: 

default-lease-time 600; 

Server responds with times like this (as seen in wireshark capture): 

T1: 0 
T2: 0 
Preferred Lifetime: 375 
Valid Lifetime: 600 

What is logged in the log file is 7500 not 600. 

The client lease file shows the following times: 

Renew: 0 
Rebind: 0 
Preferred Lifetime: 375 
Valid Lifetime: 600 

So, it seems that the dhcp options available in on commit {} are what the client sent in instead of those the server sent in response? Is that a bug? Or do I not understand how on commit {} works? I assumed that on commit {} would have access to the options as set by the server that were sent back to the client. 
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