option length exceeds option buffer length

Patrick Trapp ptrapp at nex-tech.com
Mon Dec 12 13:34:35 UTC 2016

Just a stab in the dark, but are you passing different options for different clients? Have you introduced new options or new clients that potentially are longer than the available buffer, causing this to start happening? I am assuming this is a new error when I ask this...

I would suggest capturing some traffic and comparing the contents of the packets between those that return the error and those that do not. Someone else on this list might be able to diagnose the issue without that information, but I think it will help the rest of us.

From: dhcp-users [dhcp-users-bounces at lists.isc.org] on behalf of Denis Taranushin [tda at suttk.ru]
Sent: Monday, December 12, 2016 1:16 AM
To: dhcp-users at lists.isc.org
Subject: option length exceeds option buffer length

I have a lot of errors in logs looks like:

Subscriber-ID: SV869_CV1549 HWAddress 3c:97:e:a5:83:20
DHCPREQUEST for from 3c:97:0e:a5:83:20 (Lenovo-PC) via
DHCPACK on to 3c:97:0e:a5:83:20 (Lenovo-PC) via
parse_option_buffer: malformed option ttk-su.<unknown> (code 104):
option length exceeds option buffer length.

At that moment string "ttk-su.ru" appears  only in DHCPACK:
OPTION:  53 (  1) DHCP message type         5 (DHCPACK)
OPTION:  15 (  9) Domainname                ttk-su.ru

Why "option length exceeds option buffer length"?
Why the error appears only for some client and doesn't from others?

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