agent.remote-id matching

Andre Mamitzsch andre at
Tue Mar 6 21:32:36 UTC 2018


We are experiencing a problem with matching the agent.remote-id in a DOCSIS environment. The CMTS inserts the CM MAC in the agent.remote-id, this id is then used in subclasses on the server. I was debugging an issue where the class matching did not work -   when inspecting the lease file, I found that the agent.remote-id is stored as string ("DNm+SP“) and not as a MAC address as expected.

I analyzed the MAC address and all values are in the range between 0 and 127:

44 -> 68   -> D
4e -> 78   -> N
6d -> 109 -> m
2b -> 43   -> +
53 -> 83   -> S
50 -> 80   -> P

As a proof, I added a new subclass entry using the string and got a match when I restarted the device.

MAC addresses  seem to be converted to their ascii representation if they contain only printable ascii values. I suspect that it has something to do the the „isascii“ and „isdigit“ checks in common/options.c, beginning in line 1828.

I have tested agains 4.3.4 and 4.3.6P1 - both show the same behavior. I believe  that we had a similar issue with "hardware ethernet <MAC>“, but this was years ago and I’ m not sure. I was searching  the bug reports and the mailing list but were not able to find anything similar - so any hints or advises are welcome !



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