Author: Bob Lin

Situation: when trying to open a PDF file from Outlook, it says: Operation failed. Also the user can’t save the PDF file comes from email.

Resolution: restart the Outlook.

Situation: The Animal Hospital uses DVMax. When upgrading DVMax from v8.5 to 8.7, they can’t install DVMax client because unable to save file in Windows\download installation.

Troubleshooting: In most cases, if you can’t read files or folders, it is permissions issue. There are two resolutions.

1. Run the installation as admin.
2. Assign full permission to the user who installs the software.

Situation: The Animal Hospital uses DVMax. When upgrading DVMax from v8.5 to 8.7, they can’t continue with data read only message.

Troubleshooting: We have seen many cases like this one. There are two fixes.

1. The best way is copy the data before doing upgrade. Now we can copy it back. This is faster way to do.
2. Restore from the backup. This may take long time. Be patience.

Q: We have a FTP server for clients to download and upload files. It works for clients using FTP Active mode, but not for clients using Passive mode. Why?

A: To use passive mode, you may need to ope port rang, for example 1024 to 65535.

Situation: The client has FTP for clients to uploading or downloading files. Sometimes some users can’t access it.

Troubleshooting: 1. If the transfer settings is default, change it to Active.

2. If it uses only passive mode, make sure port 1024-65335 open on firewall.

3. If you open ports 1024-65535 for passive mode, make sure FTP server also use the same port rang. In syncplify.me, the default port range are 1-65335.

4. For security reason, you may want to create application for example FTP instead opening port rang.

Q: We see many incomplete status under Application in our Paloalto Firewall. Is this application issue or Firewall issue?

A: Based on our experience, this is Application issue. It could be the user enter incorrect credentials. Or firewall blocks the connection, for example firewall may opens a port 21 for FTP, but FTP passive mode uses port rang from 1024 to 65535.

Situation: The client has two remote servers for users to access. Internal users don’t have a problem to access the RD servers. Sometimes, outside users loss the connection after login.

Troubleshooting: 1. From Paloalto firewall Monitor, we do see some RDP connections are imcomplete.

2. We find the client has 3 Internet providers: AT&T, Comcast and WiFi. The WiFi is very slow and it was configured as backup. We temporary disable it.

3. We also created a Application override policy and put it on top of other policy. Please refer to this post:

How to create Application Override Policy in Paloalto Firewall

Situation: After migrating a computer from windows 2008 R2 to 2010 R2 server, some users can’t map the server by using NetBIOS hostname, for example server1.

Troubleshooting: 1. The server has multiple IP addresses.

2. They can’t ping the NetBIOS hostname.

3. Ping FQDN works.

Resolution: Add server main IP address to hosts and lmhosts under C:\Windows\System32\drivers\etc, for example 10.0.0.2 server1. Run nbtstat -RR or restart the client’s computer.

Situation: The client keeps having a DNS problem. Sometimes, users have a problem to access some LAN resources.

Troubleshooting: We find there is Event error relate to DNS.

Log Name: DNS Server
Event ID: 404
Level: Error
Description:
The DNS server could not bind a Transmission Control Protocol (TCP) socket to address 10.0.0.84. The event data is the error code. An IP address of 0.0.0.0 can indicate a valid “any address” configuration in which all configured IP addresses on the computer are available for use.
Restart the DNS server or reboot the computer.

In checking DNS, we find one DC uses two IP addresses. One of IP address belongs to another DC. In the IPv4 Property>Advanced>IP Settings, we find there are two IP addresses. We assume they want to enter two DCs’ IP addresses but put them in wrong place. Removing another IP address fixes the problem.

Situation: The client keeps having a DNS problem. Sometimes, users have a problem to access some LAN resources.

Troubleshooting: We find there is Event error relate to DNS.

Log Name: DNS Server
Event ID: 407
Level: Error
Description:
The DNS server could not bind a User Datagram Protocol (UDP) socket to 10.0.0.84. The event data is the error code. Restart the DNS server or reboot your computer.

In checking DNS, we find one DC uses two IP addresses. One of IP address belongs to another DC. In the IPv4 Property>Advanced>IP Settings, we find there are two IP addresses. We assume they want to enter two DCs’ IP addresses but put them in wrong place. Removing another IP address fixes the problem.