Anyone know why the ESP's DHCPOFFER includes option 43 ?
Posted: Thu Feb 08, 2018 5:12 amThe final option in the DHCPOFFER from an ESP DHCP server is an option 43 (Vendor Specific Information), containing a single sub-option 0x01 with data 0x00 0x00 0x00 0x02
It's added by this code in dhcpserver.c https://github.com/espressif/esp-idf/blob/master/components/lwip/apps/dhcpserver.c#L387 with no explanatory comments
Anyone know what this option is trhere for and how to interpret it? AFAIK ths kind of vendor-specific option only really makes sense in response to an Option 60 (VCI) from the client, but this is just hard-coded in.
[update] The only thing I've found that seems vaguely possible is a PXE Boot option 1 (PXE_MTFTP_IP) which specifies the multicast IP address for the boot file - but it wouldn't really make much sense on its own, and an IP address of 0.0.0.2 doesn't figure either.
It's added by this code in dhcpserver.c https://github.com/espressif/esp-idf/blob/master/components/lwip/apps/dhcpserver.c#L387 with no explanatory comments
Anyone know what this option is trhere for and how to interpret it? AFAIK ths kind of vendor-specific option only really makes sense in response to an Option 60 (VCI) from the client, but this is just hard-coded in.
[update] The only thing I've found that seems vaguely possible is a PXE Boot option 1 (PXE_MTFTP_IP) which specifies the multicast IP address for the boot file - but it wouldn't really make much sense on its own, and an IP address of 0.0.0.2 doesn't figure either.