I have 3 Aztech Homeplug devices at home that have been in use for more than 10 years without major problems. The units are connected to gateway router, TV and network printer respectively, and properly paired when initially installed. The home network configuration and power cabling have not been changed for years, but I ran into a weird scenario today.
WAN ---> Router ----> HomePlug 1 <======> HomePlug 2 <----- Printer
The symptom is I suddenly could no longer connect to the network printer from within the LAN using the static internal IP assigned to the printer. The LAN LED kept flashing so I was pretty sure the link was up and not a dead LAN port on the printer, so I grabbed a laptop, disabled the wireless and inserted the LAN cable from the homeplug to the laptop (instead of printer), and did a DHCP renew. Voila, I got an IP, but it was actually a public IP address, and different from the one I have on the home gateway router WAN connection!
The public IP allocated to my laptop through the Homeplug is from the same internet service provider as the one I subscribe to, and actually has an identical subnet (and mask). I started wireshark and enabled promiscuous mode, saw a large volume of broadcast from some Huawei switch I believe to be from the building network hub. That was really a lot of network broadcast.
So I tested by moving the Homeplug to other sockets at home, found 3 of them exhibiting the same issue with a public IP assigned. The rest, such as those in rooms did not have such an issue, and the expected LAN IPs were assigned. I also tried to swap that Homeplug with another one I know did not have the issue, but it started exhibiting the same after plugging to those 3 sockets. So, I believe the Homeplug units themselves should not be at fault.
So there leaves several questions :-
1. How could a public IP address have been assigned? The WAN cable from broadband provider was only inserted in the home gateway router. If a specific Homeplug cannot join the rest of the Homeplug network and thus no network connection, how could it have obtained a public IP address by DHCP (it doesn't seem that it obtained it from the home gateway router)?
2. Any chance neighbors messing with their home network or power configuration could have an impact here? Does that sound fixable?
3. I did not gain access to the WAN of my neighbor, I suppose?
WAN ---> Router ----> HomePlug 1 <======> HomePlug 2 <----- Printer
The symptom is I suddenly could no longer connect to the network printer from within the LAN using the static internal IP assigned to the printer. The LAN LED kept flashing so I was pretty sure the link was up and not a dead LAN port on the printer, so I grabbed a laptop, disabled the wireless and inserted the LAN cable from the homeplug to the laptop (instead of printer), and did a DHCP renew. Voila, I got an IP, but it was actually a public IP address, and different from the one I have on the home gateway router WAN connection!
The public IP allocated to my laptop through the Homeplug is from the same internet service provider as the one I subscribe to, and actually has an identical subnet (and mask). I started wireshark and enabled promiscuous mode, saw a large volume of broadcast from some Huawei switch I believe to be from the building network hub. That was really a lot of network broadcast.
So I tested by moving the Homeplug to other sockets at home, found 3 of them exhibiting the same issue with a public IP assigned. The rest, such as those in rooms did not have such an issue, and the expected LAN IPs were assigned. I also tried to swap that Homeplug with another one I know did not have the issue, but it started exhibiting the same after plugging to those 3 sockets. So, I believe the Homeplug units themselves should not be at fault.
So there leaves several questions :-
1. How could a public IP address have been assigned? The WAN cable from broadband provider was only inserted in the home gateway router. If a specific Homeplug cannot join the rest of the Homeplug network and thus no network connection, how could it have obtained a public IP address by DHCP (it doesn't seem that it obtained it from the home gateway router)?
2. Any chance neighbors messing with their home network or power configuration could have an impact here? Does that sound fixable?
3. I did not gain access to the WAN of my neighbor, I suppose?