Possible dhclient bug ?

NOYB

May have discovered a bug in dhclient

When the client identifier type is 0 (0x00) the option is not sent.
/sbin/dhclient -c /var/etc/dhclient_wan.conf -l /var/db/dhclient.leases.em0 -d em0

However the ISC version works as expected. Sending the dhcp client option with type 0 (0x00) followed by the specified string.
/usr/local/sbin/dhclient -cf /var/etc/dhclient_wan.conf -lf /var/db/dhclient.leases.em0 -d em0

/var/etc/dhclient_wan.conf
. . .


# DHCP Protocol Options
#send dhcp-client-identifier "MYCIDX";     # Type 0x4D (non-spec type) - Sent
#send dhcp-client-identifier " MYCIDX";    # Type 0x20 (InfiniBand) - Sent
 send dhcp-client-identifier "nulMYCIDX";  # Type 0x00 (other) - Not Sent
#send dhcp-client-identifier "sohMYCIDX";  # Type 0x01 (Ethernet) - Sent

. . .
EOF

Client Identifier

The code for this option is 61, and its minimum length is 2. The type and at least one additional byte (character).

Code Len Type Client-Identifier
+–---+-----+-----+-----+-----+---
| 61 | n | t1 | i1 | i2 | ...
+-----+-----+-----+-----+-----+---

A hardware type of 0 (zero) should be used when the value field contains an identifier other than a hardware address (e.g. a fully qualified domain name).

jimp

If it's in the FreeBSD base system dhclient you should file a PR against FreeBSD directly. At least from the description it sounds as though it may be a bug.