DHCP reconfigure

RouterOS General
1

Hi,

I am trying to use the DHCP reconfigure function between two Mikrotik devices; one being a dhcp server and the other a client.
I have enabled DHCP debug on the client and the following message appears in the log:

HMAC-MD5 do not match, received 696f9a759ba5fb2db865c5c30a7d4365, computed 5b37f0f069cc959fca6e2498b212a8ca

How should I set it up so that it works?

Thanks,

Geo

2

It works for me between main router and test CHR, both running 7.23.1:

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Setting on DHCP client:

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image625×124 3.32 KB

Setting on DHCP server:

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image229×154 2.29 KB

3

Of course I made the settings. The command is sent but they don't match. DHCP Snooping is activated and between the client and the dhcp server is a CHR328 switch with dhcp Snooping enabled.

4

When you open the lease entry on the server, does the value in the Reconfigure Key field (Active tab) match the value in the Reconfigure Key field (Status tab) of the DHCP client on the other router?

I did further tests with DHCP Snooping enabled and between two CHR instances, and there was no different. FORCERENEW still works.

Do you have something else between the two devices that might reorder the DHCP options / insert new ones? It's not DHCP Snooping because that only inserts Option 82 on packets going from client to server. The messages from server to client (where the HMAC-MD5 calculation applies) is not modified by the DHCP Snooping Add Option 82 setting.

5

Is the same.

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image1522×620 110 KB

6

You could try the newest 7.24rc1 version, it has a fix related to forcerenew