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Orbi WiFi 7 RBE973
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Re: GSM7224P VLAN Routing and DHCP issues

Fusion98
Aspirant

GSM7224P VLAN Routing and DHCP issues

Hi

My pc O/S - WIndows 10 Pro, Firmaware of switch - 10.0.1.21, live office envionment.

This switch does vlan routing for our 4 vlans.  I have attempted to move the vlan routing to a different switch (HP) but inorder to do so i have to remove the entry from this switch and then enter then in the HP switch.  This should produce an instant migration however the network (all HP switches) takes several hours to update and i had to put the VLAN routing back onto the netgear switch.  Since then we have had speradic DHCP issues and DNS issues which were not around prior to the attempted migration.

On a network with approximately 250 units the DHCP requests recieved is now 701308 and climbing rapidly, the requests relayed however is far less at 90746 and it has Zero (0) packets discarded.  DHCP relay is enabled and is pointing to the correct DHCP server.  If you connect a laptop to any of the VLANS it works and gets an address, plug anything else in (raspberry pi, mitel phone) then they struggle to get an IP address.  DHCP server is not the issue.

 

1) Why is there a difference between the DHCP recieved and those relayed?

2) Why would DNS and DHCP issues be occuring after vlan routing is put back as before?  IS this the ARP tables in the switches?

3) Can you give me any pointers as to why moving VLAN Routing would cause network wide black out for x hours when another vlan works fine on the 2nd switch?

4) Can you recommend any network software that i could use to find issues on our network, such as a broken switch or somehting issuing large amounts of network packets - please not wireshark.

 

I have uploaded the files from the swtich to switch_support@netgear.com

 

Any help is greatly apopreciated

 

Model: M4100-24G-PoE+ (GSM7224Pv1h2)|ProSAFE 24-port Gigabit Fully Managed L2 Switch with PoE+
Message 1 of 8

Accepted Solutions
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

Hi

Finally figured out what it was.  The firewall has a DOS settings for both INTERNAL and external, god knows why internal.  Anyhow there is a setting for the speed of your network and one for the speed of your internet.  We upgraded our network and internet so the draytek firewall was doing its nut thinking we were under attack and stopped all traffic.  Problem is now resolved, many thanks

View solution in original post

Message 8 of 8

All Replies
Retired_Member
Not applicable

Re: GSM7224P VLAN Routing and DHCP issues

Hi Fusion98,

 

Welcome to Netgear Community.

From msg.txt, APR replied are invalid, so we guess, there must have large of ARP request/reply, which cause the network congested. there might a kind of ARP attack. can you help enable dymanic ARP inspection? refer page P240 of Admin Manual

Also would you like to answer below couple of questions?

1> any configuration or topoloy change before/after network migration? if yes, what're they?

2> Which device owning IP 192.168.0.1 and MAC 00:50:7f:e7:ce:68?

Message 2 of 8
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

Hello,

Many thanks for the help, it is REALLY appreciated.

1) the only change i have made apart from trying to move the VLAN routing was to swap the Draytek firewall (192.168.0.1) for an identicle unit as it appears to be either (a) swamped and can not cope with the requests (b) broken and stuck as non responsive.  This fixed an initial problem however two days later the replacement unit had the same issues as the original, so i'm guessing its not broken just swamped by requests.

I will enable ARP inspection and take a look at the results.  What i can not understand is why the ARP tables dont update right away?  If i move vlan routing from switch a (192.168.0.210) to switch b (192.168.0.217) then yes all the ARP tables in the network switches need to update to reflect this.  I did not expect this to take days / weeks on such a small network.

Apart from the two changes above nothing has changed.  We do however from time to time get our entire network swampped to the point where the firewall and servers become unresponsive and we can not seem to locate what is causing it.  We have swapped out switches we thought may be causing the problem (4 months ago) but every so often the problem re-occurs.  We have locked down access to the WIFI, and prevented unauthorised devices connecting to the network.  We are stumpped.

Can you recommend anything to locate what may be causing it, or could it be related to this ARP attack?

 

Once again, really appreciate your help

kind regards

John

 

Message 3 of 8
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

Hi

the PDF in the link is broken and does not download, is there another copy somewhere?

many thanks

john

 

Message 4 of 8
Retired_Member
Not applicable

Re: GSM7224P VLAN Routing and DHCP issues

Hi Fusion98,

 

Thanks for your feedback.

User Manual link is clickable, I just checked, can you try more time?

To answer your ARP question, once network topology change (e.g. routing interface or routing table), ARP table will be flushed immediately. So your problem is not related with ARP update, more looks like ARP traffic flood.

Also, can you help check who owning IP 192.168.0.1 and MAC 00:50:7f:e7:ce:68?

Message 5 of 8
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

Hi

I did as the manual suggests and only on the wifi vlan.  The entire switch locked up and stopped functioning meaning that my entire domain and all the manufacturing equipment also stopped.  I had to reboot the device and then upload a previous config.

Any other ideas i could try?

 

Message 6 of 8
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

the ip address of 192.168.0.1 with the mac address you supplied is our main firewall.

I think the issues are hidden as all of the switches in the network use 192,168.0.1 as the gateway, it then (the firewall) has static routes in place to redirect traffic if needed to the netgear switch if accessing a seperate vlan is required.

From the netgears point of view all traffic comes from the firewall.

Message 7 of 8
Fusion98
Aspirant

Re: GSM7224P VLAN Routing and DHCP issues

Hi

Finally figured out what it was.  The firewall has a DOS settings for both INTERNAL and external, god knows why internal.  Anyhow there is a setting for the speed of your network and one for the speed of your internet.  We upgraded our network and internet so the draytek firewall was doing its nut thinking we were under attack and stopped all traffic.  Problem is now resolved, many thanks

Message 8 of 8
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