10-30-2023 10:17 AM - edited 10-30-2023 05:31 PM
I have the following network (see attachment):
Router's interfaces:
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0 unassigned YES NVRAM administratively down down
FastEthernet0 unassigned YES unset up up
FastEthernet1 unassigned YES unset up up
FastEthernet2 unassigned YES unset up down
FastEthernet3 unassigned YES unset up down
Serial0 unassigned YES NVRAM administratively down down
Wlan-GigabitEthernet0 unassigned YES unset up up
wlan-ap0 192.168.0.1 YES TFTP up up
Cellular0 unassigned YES IPCP administratively down down
Vlan1 192.168.0.1 YES manual up up
embedded AP's interfaces:
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0 unassigned YES NVRAM up up
Dot11Radio0 unassigned YES NVRAM up up
Dot11Radio1 unassigned YES NVRAM administratively down down
BVI1 192.168.0.2 YES manual up up
AP's gig0 and dot11radio0 are in the same bridge group.
When I ping 192.168.0.255 from a pc I get a response from all wired hosts, wlan's hosts and AP's BVI1 dont respond. When I ping from a laptop, I only get a response from BVI1. Why is that? Arent all hosts on the same vlan? Isnt there a bridge forwarding all frames from the lan to the wlan and vice versa?
Edit:
After restarting PT and trying again I found that the ping fails as long as BVI1 has an ip. When BVI1 has no ip, the broadcast reaches all host, but the moment BVI1 gets its ip the ping stops working as it should. I also found that changes to the BVI1 ip do not persist after reload (I made sure to use write memory), so I am forced to get the ip though dhcp. I've updated the attachment.
Edit 2:
After following the packets using simulation mode, I found what goes wrong. When AP's gig0 receives the ICMP request, it immediately constructs a reply and tries to send it to the source IP (it does not forward the request to the dot11radio0 interface, thats why wlan hosts dont respond). Because it doesnt have the source's MAC it constructs a ARP request, but instead of sending it back through gig0 it forwards it to dot11radio0. So only the wlan hosts receive the ARP for the MAC of a wired host, and of course they dont respond. Is this behavior result of a misconfiguration or misunderstanding of bridges on my part? Or is it a PT bug?
10-30-2023 12:42 PM
Possibly because WLANs don't use the same broadcast rules as wired LANs.
10-30-2023 01:09 PM
I think it's working; PT can get stuck sometimes; Re-open your lab or get one u just shared here and open it.
10-30-2023 01:57 PM
Ah, good reminder about PT can be "quirky".
I.e. whatever PT results, remember they can be incorrect.
10-30-2023 03:53 PM
After trying again I found more weird behavior. If I try to manually set BVI1 ip address the configuration is lost on reload (even after write memory), I am forced to get an ip through dhcp. Even weirder, the moment BVI1 get's its ip through dhcp pings to 192.168.0.255 stop reaching wlan hosts. Could this be a glitch of PT? I cant find a reason that would explain the network breaking simply because BVI1 has an ip. I've updated my post with a new attachment.
10-31-2023 12:16 AM
nothing like that here; PT works fine on Windows; There are several posts about PT problems on MACs and Ubuntu; Search here also see CLN https://learningnetwork.cisco.com/s/discussions
Regards, ML
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