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jundesanjose
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DHCP client Ether1 looses IP address every1-5 minutes

Tue Nov 17, 2020 8:57 am

Having read through the net, it seems this issue is still present.

Here is my situation, I have a Hex unit that I am trying to upgrade to a RB4011. When I hook up the 4011, i get this errors. But when I return the Hex, there is no error. Here are the actions I've taken so far.

- Upgraded 4011 to latest stable release 6.47.7
- Used a new Cat6 cable between 4011 and modem
- Replaced the 4011, thinking it maybe a defective port.

Additional Info:
- The Hex has the latest 6.47.7 stable release.
- No fancy setup. Modem-Router-PCs with basic setup from scratch on both.
- 4011 came in with 6.49.9

Error Log (will repeat every 1-5 minutes on the 4011)
- ether1 link down
- dhcp-client on ether1 lost IP address xx.xx.xx.xx - lease stopped locally
- ether1 link up
- dhcp-client on ether1 got IP address xx.xx.xx.xx

(xx.xx.xx.xx remains the same)

What gets me is with the same package version, the 4011 looses IP address every few minutes while the Hex has been rock solid. Should I just stay with the Hex? Is there a hardware difference between the Hex and 4011 that the programmers missed? It seems that version 6.41 is the one that does not produce the errors for the 4011 as the errors started coming out with 6.42 but I prefer not to use an old package if it affects security.

Any insight into the issue is appreciated.
 
howdey57
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Re: DHCP client Ether1 looses IP address every1-5 minutes

Thu Apr 22, 2021 9:05 am

I'm on a RB4011 on 6.48.2 and get the same problem. DHCP "Lease stopped locally" on my WAN connection through a Virgin Media router in modem mode. Seemingly randomly approx once an hour.

I have put in a new cable so I don't think it is hardware related.

Did you find anything out?

Charles
 
sindy
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Re: DHCP client Ether1 looses IP address every1-5 minutes

Sun Apr 25, 2021 3:44 pm

As you've explicitly asked for a response in this thread:

1. /tool sniffer set file-name=dhcp.pcap file-limit=100000 filter-interface=your-wan-interface-name filter-ip-protocol=udp filter-port=bootps
2. make sure that all other filter-xxx fields of /tool sniffer settings are empty
3. /tool sniffer start
...return to your daily life and occasionally check for the "lease stopped locally" in the log...
Once it appears,
4. /tool sniffer stop
5. download the dhcp.pcap file and open it using Wireshark

The file may contain DHCP messages from other devices if the ISP doesn't use port isolation on their switches (most do).

In the file, you should see what was going on before it finally failed with "lease stopped locally". In any DHCPACK you've received, there is Option 51 - IP address lease time. Unless the server has specified otherwise using Option 58 and Option 59, the client should start attempting to renew the lease at 1/2 of that time, and if that fails, it should start "rebinding" at 0.875 of that time, which means it then sends the DHCPREQUEST messages to the broadcast address. Throughout all that time until the lease expires, it keeps using the address; it must stop using it once the lease expires or once it gets another one.
 
howdey57
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Re: DHCP client Ether1 looses IP address every1-5 minutes

Mon Apr 26, 2021 10:48 am

OK, got that.

Option 51 gives IP Address Lease Time: (400209s) 4 days, 15 hours, 10 minutes, 9 seconds

The order of the packets is:
Log Entry @ Apr/26/2021 06:37:05 -> "dhcp-client on ether1 lost IP address x.x.235.129 - lease stopped locally"
From my router: Discover @ Arrival Time: Apr 26, 2021 06:37:09.476903000 GMT Summer Time
From VM router: Offer @ Arrival Time: Apr 26, 2021 06:37:09.520132000 GMT Summer Time
From my router: Request @ Arrival Time: Apr 26, 2021 06:37:09.520294000 GMT Summer Time
From VM router: Ack @ Arrival Time: Apr 26, 2021 06:37:09.546760000 GMT Summer Time

Depending on clock sync, of course.

You have to wonder why my router is even sending the Discovery packet? Why does it need to? My router presumably thinks it needs to send it and logs "dhcp-client on ether1 lost IP address x.x.235.129 - lease stopped locally"

That might be a problem at my end.

Charles
 
howdey57
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Posts: 122
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Re: DHCP client Ether1 looses IP address every1-5 minutes

Sat May 01, 2021 3:27 pm

So for completeness and to help others....

The problem was the ISP Virgin Media in London. After lots of investigation of my network I came to the conclusion it was their cable modem (actually a cable router "Super Hub 4" in modem mode). After the usual long wait time I spoke to a tech who ssh'd into their cable modem and altered the signal strength (signal to noise) and since then I have had no dropouts at all - none!

My investigations included
  • The investigations in this thread
  • Logging EVERYTHING ie logging without topics - including 10 x log files of 1000 lines each which meant I was able to capture all the events. I did that because I didn't know what else might have happened before ether1 lost its connection. I found NO strange events before the lost connection, so decided it must be a hardware fault.
  • I moved the WAN connection to ether2 to see it it was my Mikrotik - same thing happened so it was not ether2
  • I therefore assumed it was a Virgin Media Ethernet issue so rang Virgin to ask for a replacement Cable Modem
It was whilst asking for a replacement modem that the tech man altered the signal strength. It was like he knew what the issue was and tweaked the settings once he'd looked at it from his end. Why does it require me to call them to get that right? hmm.

So the moral of the story is, if you do not have a stable ISP connection, don't assume it is your Mikerotik but ring your ISP and ensure you have their best signal strength.

Charles
 
ColinM9991
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Joined: Tue May 25, 2021 4:06 pm

Re: DHCP client Ether1 looses IP address every1-5 minutes

Sun Jun 20, 2021 10:02 pm

So for completeness and to help others....

The problem was the ISP Virgin Media in London. After lots of investigation of my network I came to the conclusion it was their cable modem (actually a cable router "Super Hub 4" in modem mode). After the usual long wait time I spoke to a tech who ssh'd into their cable modem and altered the signal strength (signal to noise) and since then I have had no dropouts at all - none!

My investigations included
  • The investigations in this thread
  • Logging EVERYTHING ie logging without topics - including 10 x log files of 1000 lines each which meant I was able to capture all the events. I did that because I didn't know what else might have happened before ether1 lost its connection. I found NO strange events before the lost connection, so decided it must be a hardware fault.
  • I moved the WAN connection to ether2 to see it it was my Mikrotik - same thing happened so it was not ether2
  • I therefore assumed it was a Virgin Media Ethernet issue so rang Virgin to ask for a replacement Cable Modem
It was whilst asking for a replacement modem that the tech man altered the signal strength. It was like he knew what the issue was and tweaked the settings once he'd looked at it from his end. Why does it require me to call them to get that right? hmm.

So the moral of the story is, if you do not have a stable ISP connection, don't assume it is your Mikerotik but ring your ISP and ensure you have their best signal strength.

Charles
I'm in a similar situation and have discovered this thread whilst searching for answers. I'm also on Virgin Media with the Super Hub 4 on their "1Gig" package. I have come to an impression that the VM equipment is the problem and it's causing intermittent bouts of downtime which is quite annoying.

Have you experienced this since? Do you know exactly what he modified? I'm going to have to phone Virgin Media again to unravel a web of nonsense with their standard tech support. I phoned last week, stated I was using CAT6 directly from my router to the PC, and was told that I should download an app to "search for blackspots" in the apartment.
 
sodekcz
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Re: DHCP client Ether1 looses IP address every1-5 minutes

Wed Jul 19, 2023 11:22 pm

Same isuue with RB4011 + Vodafone Station cable modem. Tested two RB4011. Inserted RB951G in switch mode between modem and 4011. It works well. Don't like that solution (+ one device in the middle) but works .... Both upgraded to ROS 7.10.2

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