Openwrt system default option(57)= 0x0240, What I want that option(57) = 05dc , how can I do that ? Thank you very much!
By reading wiki and modifying config?
- https://openwrt.org/docs/guide-user/base-system/dhcp#dhcp_pools
See 'dhcp_option' in the DHCP config. First item in the DHCP pool options.
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have you tried adding option 57 in LAN settings >> DHCP server >> Advanced settings, In my case I only need option 6 but You can add more if you want
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I mean I make openwrt as a client and get ip from upstream DHCP
That is actually the default.
What is your actual problem with the upstream DHCP?
Why does the option 57 even surface on your thoughts?
We all thought that you are taking about DHCP for LAN, which is actually managed by OpenWrt...
The upstream side, OpenWrt being the DHCP client, only involves the busybox udhcpc client, but there is not much config possibilities for that.
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To change option 57 Maximum DHCP Message Size from the default of 576 bytes (0x240) to 1500 bytes (0x5dc), use the sendopts setting:
config interface 'wan'
option proto 'dhcp'
option sendopts '57:05dc'
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thank you! what I mean is what you say above