Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

IP SCAN Through ASA VPN

Posted on 2010-08-24
6
Medium Priority
?
744 Views
Last Modified: 2012-05-10
Hello, I have a group of techs that need to scan subnets and get dns addresses from ranges at remote sites. They asa vpn group can obtain machine names in the colo; however, the remote sites use a different dns server. I have added 53 and 161 access to all of these networks; however, with the vpn filter the guys cannot get machine names. They can without the filter. Any idea what could be going on? I called cisco tac, but the person wasn't getting anywhere.
0
Comment
Question by:dcawood
6 Comments
 
LVL 16

Expert Comment

by:btassure
ID: 33520049
Can you show us a network diagram including the servers please?

Also any bits of the config you have such as the VPN groups and access lists (sanitised) please.
0
 
LVL 7

Expert Comment

by:Boilermaker85
ID: 33520890
The machine(s) from which these scans originate will try to resolve names via its own dns configuration. If the remote devices are not registering with this Dns, those lookups will fail. But most scanners will then try netbios name lookup, udp 137. If you allow that, you should be able to get their windows names.
0
 
LVL 57

Accepted Solution

by:
giltjr earned 2000 total points
ID: 33521527
In your DNS server you may need to setup a forwarder zone for the colo's IP subnet pointing to the dns server that holds their PTR records.

Right now without the filter you may be doing netbios name lookup as Boilermaker85 has suggested.
0
Choose an Exciting Career in Cybersecurity

Help prevent cyber-threats and provide solutions to safeguard our global digital economy. Earn your MS in Cybersecurity. WGU’s MSCSIA degree program was designed in collaboration with national intelligence organizations and IT industry leaders.

 

Author Comment

by:dcawood
ID: 33522379
The VPN connection has the same DNS Server as I do on the inside. I have allowed udp/137 udp/161 and udp 53 to the networks being scanned and the dns server.

When I do a scan from the inside, and get the machine names, I see on the logg monitor that it is resolving via 137 to the machine ip. Weird thing is, 137 is allowed and I dont see anything blocked in the logs.
0
 

Author Comment

by:dcawood
ID: 33522909
The traffic is being built through the vpn asa and the core asa to the vdmz where the machines are?
0
 
LVL 7

Expert Comment

by:Boilermaker85
ID: 33523083
Hard to tell from your last comment, since we dont have a picture of the network and which ASA config we need to look at.
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Many of the companies I’ve worked with have embraced cloud solutions due to their desire to “get out of the datacenter business.” The ability to achieve better security and availability, and the speed with which they are able to deploy, is far grea…
Let’s face it: one of the reasons your organization chose a SaaS solution (whether Microsoft Dynamics 365, Netsuite or SAP) is that it is subscription-based. The upkeep is done. Or so you think.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

971 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question