Hi. There is only one (fairly sticky) IP on a residential VM service. We have (not by choice) quite a stack of Mikrotiks’ behind VM routers in bridge mode, and essentially we have to create a VPN tunnel from the MT to “our end” to gain access to SNMP and SSH on the MT.
If you SSH to the IP that is supposedly bridged to the MT you get an obvious dropped session (which doesn’t show in a wireshark between the MT and VM router). Same applies to SNMP. Even if you enable the SNMP on the VM box in none bridge mode, you can’t (via the gui and from what I recall via SSH either) enable it on the outside interface. That’s it in summary. Nothing too clever. Peter Knapp From: [email protected] [mailto:[email protected]] On Behalf Of Aled Morris Sent: 02 May 2014 10:23 To: Peter Knapp Cc: Martin J. Levy; [email protected] Subject: Re: [uknof] Virgin Media - router vs modem? On 2 May 2014 10:16, Peter Knapp <[email protected]<mailto:[email protected]>> wrote: As Gary says. However please note that it doesn't put SSH or SNMP ports into pass-thru and maintains these as captive on the router so it isn't a 100% bridge (just to naff you off if you want to SNMP a device behind it from the outside) I'm intrigued by this (though I don't have VM so this is purely an academic inquiry) I'd have thought that as a "modem" the VM box would be doing a simple media conversion between DOCSIS cable and Ethernet, like a L2 bridge. The new router, behind the modem, would be doing the DHCP or PPPoE or whatever is needed to get L3 connectivity into the VM network, right? Is there MAC address spoofing going on too? So how is the "modem" interacting at L3? What IP address does it use in order to speak SSH and SNMP? Aled
