option 82 logging error

[Marc Perea]

It's been a few weeks and I've changed my log line in the dhcpd.conf to:

if exists agent.circuit-id {log(info,concat(binary-to-ascii(10,8,".",leased-address)," ASSIGNED TO AGENT.CIRCUIT-ID => ",option agent.circuit-id));}

to make the syslog more readable. Unfortunately, I'm still having an issue where the daemon is reporting an error about parsing the option, and I was hoping someone could tell me what can be done to resolve the error or even attempt to troubleshoot the root cause. If I comment out this line in the .conf, the errors go away and I obviously no longer receive syslog about my option82 info. My current syslog looks like this for every DHCP offer that completes the DORA process:

Dec 11 08:34:15 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464737:50) larger than buffer.
Dec 11 08:34:15 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464737:50) larger than buffer.
Dec 11 08:34:15 isg-dhcp dhcpd: [ID 702911 daemon.info] DHCPDISCOVER from 00:1a:2b:12:13:6a via a.b.c.d
Dec 11 08:34:16 isg-dhcp dhcpd: [ID 702911 daemon.info] DHCPOFFER on z.y.x.v to 00:1a:2b:12:13:6a via a.b.c.d
Dec 11 08:34:16 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464737:50) larger than buffer.
Dec 11 08:34:16 isg-dhcp dhcpd: [ID 702911 daemon.info] a.b.c.d ASSIGNED TO AGENT.CIRCUIT-ID => 10.11.50.116:1-9-43-0-adsl-0-35-943
Dec 11 08:34:16 isg-dhcp dhcpd: [ID 702911 daemon.info] DHCPREQUEST for z.y.x.v (e.f.g.h) from 00:1a:2b:12:13:6a via a.b.c.d
Dec 11 08:34:16 isg-dhcp dhcpd: [ID 702911 daemon.info] DHCPACK on z.y.x.v 00:1a:2b:12:13:6a via a.b.c.d

I'm also wondering if my error here is causing me trouble when I'm trying to find out who swapped out a modem. For example, my setup is such that any single agent.circuit-id should always get assigned the same IP, and only 1 lease is allowed per CID. This allows the company to install a company owned device at the customer premise, and the customer can't just replace that device without our knowledge. My log when something like this happens shows:

Dec 10 21:54:43 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464946:49) larger than buffer.
Dec 10 21:54:43 isg-dhcp dhcpd: [ID 702911 daemon.error] parse_option_buffer: option <unknown> (808464946:49) larger than buffer.
Dec 10 21:54:43 isg-dhcp dhcpd: [ID 702911 daemon.error] DHCPDISCOVER from 2a:22:15:7e:fc:bb via a.b.c.d: network isg-test: no free leases
Dec 10 21:54:43 isg-dhcp dhcpd: [ID 702911 daemon.error] DHCPDISCOVER from 2a:22:15:7e:fc:bb via a.b.c.d: network isg-test: no free leases

The no free leases is expected, since whatever CID, which is also a defined class in the .conf, is only allowed 1 lease. The problem here is, I don't know _which_ CID is currently broken!

I also verified that it's the option agent.circuit-id that's the cause of this by commenting out all other log lines in the .conf and logging just that variable with no other formatting/variables. Same thing as before - with DORA it would print 2 parse errors, the CID, then another parse error (in addition to the normal DORA logging). In a no free leases state, the same 2 errors, then 2 discovers appears over and over. Anyone know what (808464946:49) this is trying to indicate? Is my option82 info too large for the data type of the variable it's being placed in?

Per the previous response to my message, I tried using binary-to-ascii(10,8,".",option agent.circuit-id), but syslog looked the same except displaying the decimal representation of the ASCII separated by periods, like so:
Dec 11 01:21:59 isg-dhcp dhcpd: [ID 702911 daemon.info] z.x.y.v ASSIGNED TO AGENT.CIRCUIT-ID => 49.48.46.49.53.48.46.49.50.52.46.49.48.53.58.49.45.49.55.45.52.54.45.48.45.97.100.115.108.45.48.45.51.53.45.49.55.52.54

which is the same as my ASCII CID => 10.150... the same errors in the same locations as just letting it spit out the ASCII, as above.

I don't know where else to look or what else to try. If anyone has any ideas or knowledge to share, please do.

Marc Perea
Network Support Engineer
SRT Communications, Inc.
(701)858-5235
marccp at srttel.com