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Krisken
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vlan + dhcp server

Sat Apr 05, 2014 3:53 pm

Is it possible that the DHCP server doesn't work on vlans (mikrotik 6.11)?
Still a bug?
 
bingo220
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Re: vlan + dhcp server

Sat Apr 05, 2014 7:17 pm

I have 24 vlans with 24 dhcp servers, as yet works fine.
CCR-1016, ROS 6.11.
 
Clauu
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Re: vlan + dhcp server

Sat Apr 05, 2014 9:45 pm

Maybe you're trying to create vlans on ports directly without using a switch?
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lelo
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Re: vlan + dhcp server

Sun Apr 06, 2014 7:26 pm

After upgrade from ROS 5.26 to 6.11 on RB1100AHx2, DHCP on vlan interfaces has stopped functioning properly.
The log says, the offer is sent to host with no success. The leases tab on DHCP show hosts with offered status (not bound).

I have tried to create bridge, adding vlan interface to bridge, and bound DHCP server to bridge with no success.

So I think it is definitely a bug.
 
lelo
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Re: vlan + dhcp server

Tue May 13, 2014 1:03 pm

Ok, we are resolving issue, [Ticket#2014042366000345].

What we already know:

In my case, the reson for which after upgrade to ROS 6.11/12 from 5.26 the DHCP server bounded to VLAN interface has stopped working is SWITCH !!
Yes, it is D-LINK DGS-1210-52 with DHCP Screening Feature (which allows only specified DHCP servers on specified ports to send offers). After entering here IP address of Mikrotik DHCP server, everything is working fine.

But, the question is, why DHCP on ROS 5.26 was working without IP address entered on switch.
This could be actually ROS 5.x bug, not 6.x :))
We will compare the offer packets structure from both ROS versions, and maybe find the answer.
 
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Chupaka
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Re: vlan + dhcp server

Wed May 14, 2014 1:12 am

yup, we have D-Link DES-3028 switches with DHCP Relay enabled, and v6 DHCP server leases IP addresses without default gateway (and, IIRC, with incorrect subnet mask). after disabling DHCP relay client gets correct settings

because of that we've moved to using virtual machine with v5.26 for DHCP :)
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Chupaka
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Re: vlan + dhcp server

Wed Sep 17, 2014 4:16 pm

lelo, any news?
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tania
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Re: vlan + dhcp server

Sun Jan 11, 2015 10:55 am

 
lelo
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Re: vlan + dhcp server

Mon Jan 12, 2015 9:22 pm

Chupaka, I have given reply above. In my case the real reason was not Mikrotik but D-Link switch, that has no setting of allowed DHCP servers (DHCP screening feature)
The strange thing is, that it was working on ROS 5.x. without proper config on switch, but it was not normal condition.
Something must have changed in DHCP respones from 5.x to 6.x, but to investigate that it would be neccessary to perform packet capture and compare both responses.
 
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Chupaka
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Re: vlan + dhcp server

Mon Jan 12, 2015 9:27 pm

well, I just thought you were going to compare packets from v5 and v6 :(

we don't use screening, just plain DHCP Relay on switches. also, those switches work with many linux and bsd servers, so I think it's v6 who have broken DHCP server, not v5
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