Connectivity issues to Web GUI on first launch

funnybeing737 · April 02, 2024, 02:22:15 PM

Hi,

I have simple network topology

Inet -> PPPOE -> OPNsense -> admin pc (192.168.1.1)

Inet -> PPPOE -> OPNsense -> user pc (192.168.2.1)

First time after installation, I have assigned and configured the network interfaces with IP addresses as above. No other firewall rules or packages installed yet. WAN is also not connected.

I find that as soon as I connect the web browser to point to the opnsense URL from a browser, the ARP connectivity fails.

I have checked ping before launching the browser, that works

I have checked arp output and it is all good (see below)

I have checked curl output and that is good too.

But right after I launch the browser to connect to the device the connectivity fails.

Why is this problem happening?

---------------------------------------------------------------------------------------------------------

I connect to the admin pc to open the web gui:

test ping to 192.168.1.1 succeeds

C:\Users\Localuser>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Reply from 192.168.1.1: bytes=32 time=1ms TTL=64

Reply from 192.168.1.1: bytes=32 time=1ms TTL=64

2) ARP check

C:\Users\Localuser>arp -a

Interface: 192.168.1.100 --- 0xa

Internet Address Physical Address Type

192.168.1.100-e0-4c-68-00-c1 dynamic

192.168.1.255ff-ff-ff-ff-ff-ff static

224.0.0.2201-00-5e-00-00-16 static

224.0.0.25101-00-5e-00-00-fb static

224.0.0.25201-00-5e-00-00-fc static

255.255.255.255ff-ff-ff-ff-ff-ff static

3) CURL check

C:\Users\Localuser>curl http://192.168.1.1

<!doctype html>

<html lang="en" class="no-js">

<head>

<meta charset="UTF-8" />

<meta http-equiv="X-UA-Compatible" content="IE=edge">

<meta name="robots" content="noindex, nofollow" />

<meta name="keywords" content="" />

<meta name="description" content="" />

<meta name="copyright" content="" />

<meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1" />

<meta name="mobile-web-app-capable" content="yes">

<meta name="apple-mobile-web-app-capable" content="yes">

<title>Login | OPNsense</title>

--------------> snip <---------------------------------------------------------

4) NOW, I open a web browser and hit http://192.168.1.1 page fails to open

5) Wireshark logs show continuous ARP requests for 192.168.1.1

6) I check ARP

Interface: 192.168.1.100 --- 0xa

Internet Address Physical Address Type

192.168.1.255ff-ff-ff-ff-ff-ff static

224.0.0.2201-00-5e-00-00-16 static

224.0.0.25101-00-5e-00-00-fb static

224.0.0.25201-00-5e-00-00-fc static

255.255.255.255ff-ff-ff-ff-ff-ff static

There is a surprising entry for 192.168.1.255 which points to ff-ff-ff-ff-ff and same is repeated for 255.255.255.255

Connectivity issues to Web GUI on first launch

funnybeing737

April 02, 2024, 02:22:15 PM