Hello,

My company is currently rolling out many new devices in part of a refresh project. One of the devices being deployed at every site is an APC UPS, with a Network Management Card.

There is a team that pre-stages these devices, however, sometimes, there are typos. I've found a very weird scenario that makes absolutely no sense, whatsoever, and have seen it multiple times:

IP: 10.1.1.10
SM: 255.255.255.0
GW: 10.1.3.1 (improper)

I find that the device will still respond to pings when I am on another subnet, in my office for example, however, it WILL NOT allow for a telnet connection. As soon as the gateway is fixed, via console by a person onsite, telnet works.

So here is my question:
Is this a one off situation with APC, or is there a difference in the way ICMP and TCP packets get routed? The only thing that made sense to me is that with TCP, you must do the 3-way handshake, and with ICMP, that isn't the case - but I still can't make sense how the host is able to respond to my ping requests.

Your S.O should avoid from written that combination of IP/MASK/GATEWAY but anyway check the arp table on the computer probably you get as destination MAC address the routers MAC. So if that is the case it will work no matter what GW you wrote.

kind regards

This has happened to me before, and it completely threw my troubleshooting for a loop. It happened after a network redesign at one of my sites, not with an APC NMC, but an HP printer.

To this day I cannot explain why I could ping with an incorrect gateway on the HP. To Stretch's question, I had verified "no ip proxy-arp" was set on the interface. My router in this case was a 3750 Stack.