Marcin Jurczuk writes: > I have lab system with isc-dhcp-server and kea installed. > I stuck on issue of handling malformed packets. > ISC-DHCP handles them flawlesly yet kea throws weird error: > DEBUG DHCP4_LEASE_QUERY_PACKET_UNPACK_FAILED failed to parse query from > 10.0.0.1 to 172.16.0.10, received over interface ens18, reason: Option > parse failed. Tried to parse 161 bytes from 158-byte long buffer. > > This is not LEASE QUERY packet at all.
=> when you load the lease query hook the unpack/parsing is performed by the hook because it is the right place to intercept lease query messages. Outside the log which is a bit different the lease query hook does not apply lenient parsing even when enabled: this is a known defect described in the #4105 ticket which is currently in backlog (i.e. waiting for someone to request it to be fixed). > pcap shows this is malformed packet > where option125 length reported by CableModem is just wrong. > Below is wireshark text about exactly that packet that causes problem - it > was captured on dhcpd server. => so Kea is right in complaining about the packet to be malformed.... > To emphasise - turning off kea, starting isc-dhcp - and modem gets IP, > turning off isc-dhcp enabling kea - I'm getting this error and modem is not > getting IP. => you have at least 4 solutions: - to get client fixed (I am afraid this can't be done...) - fix packets on the flight (not so easy) - move the lease query service to another box and enable linient parsing: if it is not critical to not step parsing at the malformed option this should fix your problem - make #4105 to be addresseed (unfortunately could take time as the next release is scheduled for next year...). Thanks Francis Dupont <[email protected]> -- ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information. To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users. [email protected]
