LanSweeper Ignoring Some VOIP Phones

[MrBob]

We have two facilities that are are on separate subnets. The local subnet (172.16.x.x) is where the LanSweeper server is location. The remote subnet (172.18.x.x) is connected to the local subnet via Charter Fiber Ethernet service.

We have VOIP desktop phone at both locations. On the local subnet, the phones are scanned and show up in the Assets list. The VOIP phones on the remote subnet don't show up in the Asset list at all. These phones are within the IP range being scanned on the remote subnet. Everything scans without problem on the remote subnet.

What could cause LanSweeper to simply ignore these devices?

[Obi_1_Cinobi]

Admin note: removed the original attachments for security reasons as they contained AD credential information.

[jacob_bks]

if the phones support or listen/respond on HTTP and HTTPS (Like Cisco), I would enable that or allow HTTP... then Lansweeper will pick up the info

here's my example from device tester



Scanning TCP ports..
Open ports:
80 (HTTP)
443 (HTTPS)
Closed ports:
21 (FTP)
22 (SSH)
23 (Telnet)
25 (SMTP)
135 (EPMAP)
139 (NetBIOS Session Service)
3389 (RDP)
445 (SMB)
9100 (Jetdirect)
16992 (Vpro HTTP)
16993 (Vpro HTTPS)
Scanning netbios (UDP)..
Could not scan netbios
Scanning SIP..
Error: Socket exception TimedOut: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
Scanning HTTP..
Url: http://(ip removed)
Response Uri: http://(ip removed)/
Transfer-Encoding: chunked
Connection: close
Cache-Control: no-cache
Content-Type: text/html
Date: Thu, 07 Sep 2017 19:05:46 GMT
Expires: Thu, 26 Oct 1995 00:00:00 GMT
Server: Allegro-Software-RomPager/4.34
Title: Cisco Systems, Inc.

[MrBob]

Tech Support supplied me with an explanation of what was happening and why. They also gave me a reasonable work-around. At least selecting the "Save Pinged IP" will create a place-holder to act as a reminder to populate the info needed.

By default, Lansweeper only adds a network device to the database if data can be pulled from one or more of the following protocols: FTP, HTTP, HTTPS, JetDirect, MOB (Managed Object Browser), SIP, SMTP, SNMP (SNMPv1, SNMPv2 or SNMPv3), SSH, Telnet or WMI. SNMP usually provides the most information. As we can see in your devicetester output there are no open ports available on these assets.

The only reason why the assets in the local subnet have an asset page, is because Lansweeper queries the ARP table of your Lansweeper scanning server. ARP is a network protocol that allows you to find the MAC addresses of devices in your own IP subnet. Lansweeper currently only uses the ARP table of the Lansweeper scanning server to find MAC addresses of devices in your local subnet, and as you can see in the devicetester, a MAC address is being returned. Assets in a remote subnet will not be present in your Lansweeper scanning server's ARP table.

Alternatively, in the IP Range scanning target, there is, however, an option called Save Pinged IP. Checking Save Pinged IP will force asset pages to be generated within Lansweeper for devices without open ports. So theoretically, if you have no open ports on your assets, and you scan them with an IP Range scanning target (with Save Pinged IP-enabled) there will be asset pages generated for your assets. Keep in mind that no further asset information will be available for these assets. Of course, you can manually add more information to these assets.

[MrBob]

I am emailing tech support currently as well as posting here.

I am attaching a copy of a PDF I sent to tech support. It shows the results of running the LanSweeper Connectiontester and Devicetester on a pair of VOIP Phones and a pair of Motorola MC9200 Handheld Barcode scanners. Each pair has a local subnet device and a remote.

The tests show virtually identical outcomes.

The PDF also includes a screen capture of the resulting records created by the LanSweeper scan for the local subnet devices.

It's not clear to me why a "Network device" record is created for the local subnet scan but not for the remote subnet scan.

[jacob_bks]

and then you can be even more awesome by making a copy of the report, putting a WHERE clause where assetmacaddress like 'AB:CD:%' and deviceassetname is null or ='' and then, after you fix all the phones now..., set it to email you at an interval to then let you know when a phone comes up that's not scanned.

though make sure you filter on lastseen so you don't get old stuff on the switches... (and set it to scan you switches daily or something)

and.. well, you can just make the report without the MAC filter, and have it email you if *anything* is on the switch that you haven't scanned successfully.


yayyy

[jacob_bks]

And kind of related... but you can find the phones that you're missing by scanning the appropriate switches, and for devices you have not successfully classified or scanned, you will see MAC addresses on the ports versus a clickable device.

The first four of the MAC address (if not more) will be the same for all of the same manufacturer VOIP phones (generally speaking)...


So you can pull up the switch port report, filter it by the first four of the MAC, and it will show you what you're missing...

[jacob_bks]

Yes, run the devicetester.exe and send results...

I remember several years ago, faintly.. that you can't scan and get MAC addresses on a different subnet... so Lansweeper would need to first, be able to ping the phone from it's subnet, and second, be able to query SNMP to pick it up and grab it's MAC address - which it will then look up the device OID or whatever its called, and classify it as a VOIP phone.


But yes, support is great - be sure to post the solution here though!

[David_G]

I would recommend that you send in an email to support@lansweeper.com for troubleshooting issues, as it would be easier to investigate and help you further with the issue that you are currently facing.

It might be possible that none of the ports that Lansweeper uses to scan devices are enabled on the devices of the remote subnet. Additionally, to perform a connection test for a network device, you will have to make use of the Devicetester.exe tool found in the Program Files(x86)\Lansweeper\Tools folder on your Lansweeper server as the testconnection.exe tool is used for Windows computers only.

[MrBob]

I've checked the server log and I have found when I scan one of the VOIP phones that is on the remote subnet I do get an error message

IP range scanning 172.18.4.8 Ping OK, no open ports

This prompted me to run the LanSweeper Connection Tester. I ran a test on both a local subnet VOIP phone as well as the remote subnet (see attached PDF).

The test results were identical so that doesn't seem to explain when scanning fails completely on the remote subnet VOIP phone.