Solved

Win 2008 server lost access to network router

Posted on 2016-08-03
5
108 Views
Last Modified: 2016-08-03
Have a Win2008 server in a small LAN. It is running as a domain controller and is also running an email server. LAN is connected to Internet via a ZyWALL router (192.168.1.1), and it has worked well for a long time. Yesterday I noticed that the server seemed to not access the Internet anymore (mail server failed dns lookups to external dns). Inbound emails work fine (the server responds to external requests).

Investigation showed that the server doesn't "see" the router.
I'm able to ping the router from other devices in the LAN. From the server I'm able to ping all other addresses - except the router address. From PCs in the LAN I'm able to ping the server's IP address. This tells me that there may be something that prevent the server to access the router. Have checked the routing tables, and the address 0.0.0.0 is routed to the correct address (192.168.1.1).

Expect that there may be some process or service that prevents the server from accessing the rouer's IP addres, but I'm not able to fine what it is. The server is running Malwarebytes to prevent attacks and malware. Have tried to disable it, but not sure if I've done it right.

Are there any other steps to take in order to solve this problems?  Thanks!
0
Comment
Question by:Olaf Berli
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
5 Comments
 
LVL 28

Assisted Solution

by:Michael Pfister
Michael Pfister earned 250 total points
ID: 41740604
When the server responds to external requests there is IP connectivity between the router and the server.

Anything on the ZyWall preventing access to the Internet just for the server?
0
 

Author Comment

by:Olaf Berli
ID: 41740761
I can't see anything on the ZyWall that should create this problem. Have made a short log on it while running a ping on the server. It seems like the router sees the request, but doesn't respond. Have attached a screendump from Wireshark that displays the router log file.
wireshark.pdf
0
 
LVL 96

Accepted Solution

by:
Lee W, MVP earned 250 total points
ID: 41740826
Perhaps it's not the server that's the problem. What if your router thought it was being attacked from the server and disallowed communication with it.  

Have you tried a different router - even a cheap home one - just to test...?
0
 

Author Comment

by:Olaf Berli
ID: 41741230
Good idea!  Put in an older ZyWall 2+ and it works just as it should. Server pings the router ok and the server is able to access the internet. Need to find out why that other ZyWall didn't respond.... Haven't seen any setting that should "ban" local units....  Anyway - thanks a lot!
0
 

Author Closing Comment

by:Olaf Berli
ID: 41741234
Thanks!
0

Featured Post

Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

Question has a verified solution.

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

How to set-up an On Demand, IPSec, Site to SIte, VPN from a Draytek Vigor Router to a Cyberoam UTM Appliance. A concise guide to the settings required on both devices
This article explains how to install and use the NTBackup utility that comes with Windows Server.
This tutorial will give a short introduction and overview of Backup Exec 2012 and how to navigate and perform basic functions. Click on the Backup Exec button in the upper left corner. From here, are global settings for the application such as conne…
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…

696 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