To review, when I attach my recorder (using WIZ810MJ) to my customer’s network and try to ping it from a remote location (not on the same subnet), all pings fail. The ping requester never sees a ping reply. However, when I replace my recorder with a different device the customer has (it happens to be an ethernet to serial port bridge), that device can be pinged successfully. Both devices (my recorder and the ethernet to serial port bridge) are set to the SAME IP address (10.70.154.81) and the SAME gateway address (10.70.152.7). Of course, only one of the devices is connected to the network at a time (and they were connected to the same port on the switch, using the same ethernet cable).
Bottom line, pings to the ethernet to serial port bridge device work fine. Pings to the recorder (using WIZ810MJ) fail every time.
I have already posted a Wireshark capture file (wireshark3.zip) showing data to and from the WIZ810MJ with pings failing. For comparison purposes, I captures Wireshark data to and from the ethernet to serial port bridge device (set to IP 10.70.154.81, gateway 10.70.152.7). That Wireshark capture file is here:
wireshark4.zip (33.5 KB)
The Wireshark capture was started prior to turning on the ethernet to serial port bridge so I could see everything, including any ARP requests.
At frame 357 there is a ping request. There was no reply because the unit under test was not turned on yet.
At frame 775 there was another ping request. Frame 776 had a ping reply, but sent to the wrong MAC address. I presume the unit under test was not yet fully initialized.
At frames 1167 and 1167 there was another ping request with a reply sent to the wrong MAC address.
At frame 1607 there was another ping request, but no reply (unit under test still initializing?)
At frame 2013 there is another ping request. This time the unit under test was initialized, and an ARP request was done seeking the MAC address of the gateway. The ARP reply identified the MAC address of the gateway (IP 10.70.152.7) as 00:00:5e:00:01:82. At frame 2016 the ping reply was sent to IP 10.34.7.240 using the correct MAC address of the gateway (00:00:5e:00:01:82). This ping reply was received by the remote computer.
Thereafter there are a series of ping requests/replies, with all of the replies being properly received by the remote computer. Note that in each case the ping request comes from IP address 10.34.7.240, MAC address ec:55:67:d0:0d (the MAC address of the switch), but the ping reply is sent to IP address 10.34.7.240 using destination MAC address 00:00:5e:00:01:82 (the properly resolved MAC address of the gateway). This is 100% proper behavior, and the pings (and any remote connection requests) work perfectly.
But once again I must emphasize that neither pings nor remote connection requests work with the WIZ810MJ on this network. Why is that? It is because the WIZ810MJ is not resolving the MAC address of the gateway. It is making an invalid assumption that the MAC address where the reply should be sent is simply the MAC address of the request. This is NOT TRUE. The MAC address where the reply should be sent is the MAC address of the gateway, which must be resolved using ARP. The WIZ810MJ isn’t even bothering to do an ARP request at all to get the MAC address of the gateway.
So why is the MAC address of the gateway different than the MAC address of the received ping or connection request? I’m not 100% sure, but I’ll bet you dollars-to donuts that is it because this network is using VRRP (Virtual Router Redundancy Protocol). Once again, this is a customer’s network (a very large network at that), and I am not allowed to modify its configuration in any way. I am simply expected to make my product (using WIZ810MJ) work on his network.
Sadly, there seems to be a serious flaw in the WIZ810MJ with regard to implementation of the gateway.
For starters, I would like a detailed explanation from an engineer at Wiznet about how the gateway is implemented and under what conditions the resolved gateweay address is and is not used.
Help! What can I do to make my device work on my customer’s network?