We had a strange issue today, which i cant explain. Maybe some of you could point me to possible cause.
Application where failing because multiple file share was unavailable.
First let me explain the setup.
We have corporate forest, which exists out of four domains. These domains contain various servers. Every production site, has its own production forest, which is separated from the corporate LAN by a Firewall. Yesterday two Biztalk server lost their connections to a share on a server within the production site. This means that both server A1 and A2 in corporate, could no longer connect to shares in the various production sites at the same time while writing a file.
In our troubleshooting we tried to access the share via the command-line which failed. We tried to access that share from a third server,which worked. So the target share was available from A3, but not from A1 and A2. Other shares on other servers within the same production network were available for server A1 and A2, yet other shares on the target were not available to A1 and A2. While A3 can access all shares.
We checked the eventvwr on A1 and 2, but could not find a smoking gun. Rebooted A1 and A2, still no success. We rebooted the target server in one production site, which solved the problem for that site. So in the end we fixed it by rebooting the Share server in every effected production site (4).
Yet as this was production that was effected, we have to explain what happened and what we can do to prevent this issue from occurring again.
Antivirus:
antivirus cant be because 1 target server did not have anti virus installed.
SMB signing:
SMB signing is not enabled by default in file shares, and is not enabled by policy.
Accounts:
The security accounts used to access the share in production sites where not locked-out. And we were able to access the shares from server A3 with those credentials.
A net use time out with "network error 64". Checking dumps on the firewalls did not show anything being blocked.
Answers provided are coming from personal experience, and come with no warranty of success. I as everybody else do make mistakes.