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mlpaul
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3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 2:16 am

Hi all, I recently got new internet installed, and I've been pulling my hair out trying to get my router to pull a WAN IP from the ONU. I've called their tech support and gave them the MAC of the interface I am using (they have MAC authentication on their modems) and was told I should be good to go.

I plugged my Mikrotik in, which worked just fine on coax, and it isn't getting it's dhcp WAN ip. I tried cloning the ISP provided router's MAC with no success, I tried 2 other Mikrotik routers I have lying around and they are having the same issue. I used packet sniffer to stream to wireshark, and I see the DHCP discover, offer and ACK, but I'm not educated enough to see what the issue is in Wireshark.

So my question, is can someone look at my packet capture, and give me some insight on the issue I am having?

Thanks so much in advance,

https://drive.google.com/file/d/1ciIcvT ... drive_link Here is the packet capture file

EDIT: Solved thanks to this post viewtopic.php?t=154954
Last edited by mlpaul on Wed Jul 10, 2024 3:12 am, edited 1 time in total.
 
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mkx
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Re: 3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 8:42 am

In a nutshell:
  1. your router initiates DHCP handshake by sending out DHCP discover packet
  2. it receives initial replies from two DHCP servers (168.75.190.2 and 168.75.190.1), offering two different IP addresses (168.75.190.9 and 168.75.190.199 respectively). Both DHCP servers offer themselves as gateways, the res (subnet mask, DNS server addresses) are the same
  3. your router fails to proceed with DHCP request (from either of DHCP servers), so it doesn't receive final DHCP acknowledge ... similar to the ACKs you see (and are actually destined to other clients)
(a bit more description about how DHCP handshake looks like is e.g. in wikipedia article)

It's hard to tell why MT doesn't like the DHCP offers it received, it could be it's upset by option ordering (it should not be though), it could be it's missing some option (I've no idea which one that might be). It could be it doesn't like the fact it received two distinct DHCP offers and can't decide on which one to pursue.
Is your RB running the latest ROS available (either v6 stable, which is 6.49.15, or v7 stable, which is 7.15.2)? I seem to remember some issues with MT's DHCP (either server or client) a while ago which were fixed shortly after, but it is possible that ROS version you're running does have some issues.
 
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mlpaul
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Re: 3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 3:53 pm

I believe i am running v7.12. I can verify when I get home, however I know it's version 7. Something.

The odd thing is, I get no log messages regarding DHCP, so I'm really not sure how to go about troubleshooting this. If I use a standard off the shelf router it works just fine with no issue, but with mikrotik equipment, it does nothing with the lease offer. Calling the ISP tech support is next to useless, which I understand since technically their internet is working.
 
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Re: 3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 9:41 pm

I was doing some more searching, and I've found a couple posts with a similar issue, and they've found that in a routerOS update, the dhcp options were changed / moved around. I'm gonna try some of the solutions they used and see what happens
 
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Re: 3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 11:05 pm

Just tried the fix from the other post (adding option 57 to the client) and that didn't work. Next I'm gonna try an older version of RouterOS as I'm on 7.2, I initially tried the newest version with no effect, so I'm going to try 6.49.13 which I know is stable since I've ran that for a while.

Will update
 
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Re: 3011 Not getting WAN IP from dhcp client

Tue Jul 09, 2024 11:12 pm

Just tested, older version is doing the same thing. I think I've hit a brick wall
 
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mlpaul
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Re: 3011 Not getting WAN IP from dhcp client  [SOLVED]

Wed Jul 10, 2024 3:11 am

I was able to solve my issue using the solution from this thread: viewtopic.php?t=154954. I wasn't sure if it was going to work since I don't have ATT, but alas, it did.
 
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Re: 3011 Not getting WAN IP from dhcp client

Wed Jul 10, 2024 11:54 am

Do you mind sharing which particular part of configuration did the trick for you?
 
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Re: 3011 Not getting WAN IP from dhcp client

Wed Jul 10, 2024 4:15 pm

For sure, I had to use the bridge method. Create a bridge, disable STP, enable VLAN filtering with ingress turned off. Add ether1 to the bridge and it pulled an IP.

However, I think there may be another issue I am facing, as I'm only getting ~ half my speeds I should. I think this may just be the age of the 3011 more than anything though, because when I do a speedtest from my PC, I see the CPU on the 3011 rocket to 100% until it's done. Although, I didn't have this issue with another provider with 1gbps up and down.
 
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Re: 3011 Not getting WAN IP from dhcp client

Wed Jul 10, 2024 4:22 pm

However, I think there may be another issue I am facing, as I'm only getting ~ half my speeds I should. I think this may just be the age of the 3011 more than anything though...
Sounds about right if your ISP line is 1Gbps. Official test results, taken with a grain of salt[*], say that RB3011 is capable of routing at around 450Mbps (give or take).

Sometimes a netinstall and redoing (similar) setup from scratch may clear some configuration cludge which is not visible (or apparent) but is clogging CPU.

[*] The experience goes that the most real-life-resembling number is the one listed under "Routing -> 25 Filter rules -> 512byte packet size". For sure that in any particular use scenario the actual value can be quite a bit higher or lower, depending on actual firewall rule set.

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