Questions[connection-refused](server)

I have a situation where workstations will lose the connection to network shares and printers during the night and have to be rebooted in order to reconnect, afterwards everything works correctly, this does not happen every night, and it does not happen to every workstation. 

When clicking on a shared drive, users receive the following error “The system cannot contact a domain controller to service the authentication request. Please try again later.”

The network has three domain controllers, one SBS 2013 (we can call DCSBS), one Windows 2016 (we can call DC1) and one 2019 Standard server (we can call DC2). DCSBS handles the FSMO roles and DNS, DC1 handles DHCP and DNS and DC2 is a file server and DNS. All are Global Catalog Servers.

I raised the Forest and Domain to 2008R2 and migrated SBS 2013 from FRS to DFSR then promoted the one Windows 2016 server (DC1) and one Windows 2019 server (DC2) to Domain Controllers and moved the DHCP server from the SBS server to DC1 and everything seemed to be working just fine, but now if a workstation is dormant overnight then it needs to be rebooted in order to connect to shared resources, not every morning but most mornings. This problem seemed to start shortly after I moved the shared drives and printers to DC2, before that they were located on DCSBS, also there were some file shares on a members server that worked before and are now also affected. The users do not lose Internet connectivity just access to shared resources.

I did have an issue with a couple of workstations when I tried to use Group Policy to map drives, the drives didn’t show up so I used a logon script with the net use command and everything worked just fine.

I tested the file replication on the SYSVOL scripts directory with a text file and it replicated across all three domain controllers.

I have run the AD Replication Status Tool and everything completes successfully.

I ran DCDiag on all three DCs and received the following errors:

I found a Microsoft article “DCDIAG.EXE /E or /A or /C expected errors”. So I guess the failed DFSRevent, KccEvent and SystemLog are to be ignored.

Running DCDaig From DCSBS

Testing DCSBS: This message is reported on all DCs and all pass. Starting test: DFSREvent There are warning or error events within the last 24 hours after the SYSVOL has been shared. Failing SYSVOL replication problems may cause Group Policy problems. ......................... DCSBS passed test DFSREvent

Testing DC1: I get the same errors DFSREvent, KccEvent, SystemLog for DC2 Starting test: DFSREvent The event log DFS Replication on server DC1.domain.local could not be queried, error 0x6ba "The RPC server is unavailable." ......................... DC1 failed test DFSREvent

Starting test: KccEvent The event log Directory Service on server DC1.domain.local could not be queried, error 0x6ba "The RPC server is unavailable." ......................... DC1 failed test KccEvent

Starting test: SystemLog The event log System on server DC1.domain.local could not be queried, error 0x6ba "The RPC server is unavailable." ......................... DC1 failed test SystemLog

Running DCDaig From DC1

Testing DC2: This is a new error that I have not received in prior days DCDiag test. Starting test: Advertising Fatal Error:DsGetDcName (DC2) call failed, error 1722 The Locator could not find the server. ......................... DC2 failed test Advertising

I ran PortQryUI and all ports queried reported the same on all DCs with a return code of 0x00000000 except the following:

UDP port 88 (kerberos service): LISTENING or FILTERED portqry.exe -n 192.168.X.X -e 88 -p BOTH exits with return code 0x00000002.

UDP port 138 (netbios-dgm service): LISTENING or FILTERED portqry.exe -n 192.168.X.X -e 138 -p UDP exits with return code 0x00000002.

TCP port 42 (nameserver service): FILTERED portqry.exe -n 192.168.X.X -e 42 -p TCP exits with return code 0x00000002.

I ran Repadmin /replsum /errorsonly Repadmin Results No Fails - No Errors

Results of: DCDIAG /TEST:DNS /V /E /F:<filename.log>

Summary of DNS test results:

                    Auth Basc Forw Del  Dyn  RReg Ext

Domain: domain.local

DC2 PASS PASS PASS PASS PASS PASS n/a
DC1 PASS PASS PASS PASS PASS PASS n/a
DCSBS PASS PASS PASS PASS PASS PASS n/a

How can I force postfix to send out mails sequentially and not simultaneously? It should open only one SMTP connection at a time.

It should only affect outgoing SMTP connections. Incoming connections can still be handled simultaneously.

Why?

My VPS Provider (contabo.de) had the very funny Idea to tie the hands of spammers by limiting the number of simultaneous SMTP connections to 1. I'm not sending SPAM, but a script is sending important order mails to 3 recipients at the same time once a day. This is then blocked with Connection refused in postfix and the mails are deferred. Sometimes it takes over two hours to send the mails out, because at every try the simultaneous connections are blocked.

This is a Canonical Question about Connection Refused

We see a lot of questions to the effect

When I try to connect to a system I get a message

Connection refused

Why is this ?

I'm trying to install gitosis on a Server (hosted by OVH and running Ubuntu server 11.04). I've done it a few times and never had any problems.

But this time I have something very wired when I simply try to clone gitosis.

[root@ovks-1:~/]#git clone git://eagain.net/gitosis.git
Cloning into gitosis...
eagain.net[0: 208.78.102.120]: errno=Connection refused
fatal: unable to connect a socket (Connection refused)
zsh: exit 128   git clone git://eagain.net/gitosis.git

Based on my searches it looks like the port 9418 is closed.

But I don't understand, a server by definition shouldn't have any closed port and I can't find a way to see if they are.

So how can I check is a port is open and how can I open it if closed?

Thank you for your help.

Requested by WesleyDavid: iptables -L result

[root@odeoos-vks-1:~/]#iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination   

I have no idea what it means... Thanks :)

Update:

I finally cloned gitosis from github using https://github.com/res0nat0r/gitosis.git and it worked.

My guess is that eagain.net has an actual connection problem and that there isn't much I could do about it...

My Cassandra used to work with no problems.

I was able to connect with no problems but now for some reason it doesn't work anymore.

[default@unknown] connect localhost/9160;
Exception connecting to localhost/9160. Reason: Connection refused.

and

root# ./bin/cassandra-cli -host localhost -port 9160
Exception connecting to localhost/9160. Reason: Connection refused.

I am on Linux Ubuntu Server.

Thanks in advance...