ERROR: Failed binding SOCKET to Port 55413 and 55414

Server
1

Hi, I do have a socket error problem on my Linux Debian Server running Urbackup. I have a fresh Debian install with all dependencies installed. When I install the Urbackup server, it’s just running fine. Adding a client had some challenges but I managed to run a first backup. After that it’s not possible anymore to make a backup. Urbackup is the only service running on Debian. The client can bee seen by the Server Web Interface, but starting a backup, no way! When I do a debug of the server I get the following:

urbackupsrv run -v debug
2018-01-22 09:13:38: Starting HTTP-Server on port 55414
2018-01-22 09:13:38: ERROR: HTTP: Failed binding socket to port 55414. Another instance of this application may already be active and bound to this port.
2018-01-22 09:13:38: Started UrBackup…
2018-01-22 09:13:38: Removing temporary files…
2018-01-22 09:13:38: Recreating temporary folder…
2018-01-22 09:13:38: Testing if backup destination can handle subvolumes and snapshots…
Testing for btrfs…
ERROR: not a btrfs filesystem: /backup/testA54hj5luZtlorr494
TEST FAILED: Creating test btrfs subvolume failed
Testing for zfs…
TEST FAILED: Dataset is not set via /etc/urbackup/dataset
2018-01-22 09:13:38: Backup destination cannot handle subvolumes and snapshots. Snapshots disabled.
2018-01-22 09:13:38: Testing if backup destination can handle filesystem transactions…
MOUNT TEST OK
2018-01-22 09:13:38: Binding to interface eth0 for broadcasting…
2018-01-22 09:13:38: Broadcasting on interface IP 192.168.16.34
2018-01-22 09:13:38: UrBackup Server start up complete.
2018-01-22 09:13:38: ERROR: Failed binding SOCKET to Port 55413
2018-01-22 09:13:38: ERROR: Error while starting listening to ports. Stopping server.
2018-01-22 09:13:38: Looking for old Sessions… 0 sessions
2018-01-22 09:13:38: Exited Loop
2018-01-22 09:13:38: Deleting at…
2018-01-22 09:13:38: Deleting SelectThreads…
2018-01-22 09:13:38: Deleting lbs…
2018-01-22 09:13:38: Shutting down plugins…
2018-01-22 09:13:38: Deleting server…

The client side reports:
urbackupclientbackend -v debug
2018-01-22 09:19:04: ERROR: urbackupserver: Failed binding socket to port 35623. Another instance of this application may already be active and bound to this port.
2018-01-22 09:19:04: ERROR: Binding tcp socket to port 35621 failed. Another instance of this application may already be active and bound to this port.
2018-01-22 09:19:04: ERROR: FileServ exit with error code: 99
2018-01-22 09:19:04: Started UrBackupClient Backend…
2018-01-22 09:19:05: Looking for old Sessions… 0 sessions
2018-01-22 09:19:05: Internet mode not enabled
2018-01-22 09:19:05: Final path: /srv
2018-01-22 09:19:05: Final path: /etc
2018-01-22 09:19:05: Final path: /root
…
Firewall on the Server is off, ports on client side are open so that should be the issue. Strange thing is I have no problems at all with my live site. With my test site it will not work. No firewalls, no proxies, no switches preventing port access.

I don’t know how to fix this. After installation I had to re-install the client and server before the client was seen by the server. My guess still is somewhere on port side, but I disabled everything which could block the necessary ports.

Any help would be appreciated, as this drives me crazy.

Many thanks for looking into this.

Best regards,

Chris

2

Ok, i have investigated some network traffic between client and server. There is more going on than only 6 ports in which you should expect communication takes place. It seems that that multicast traffic is very important for the client to communicate with the server. When I open UDP 30000 until 65000 on my client I have immediate communication between server and client. The client is now backing up automatically without out doing anything.

I will monitor this for a few day’s but I believe that the solution is opening ports 30000 and 65000 between the IP addresses of your server and client.

As I know that my server has no firewall this couldn’t be the issue. Unfortunately the client is Zentyal and Zentyal is running a firewall by default. My guess is that anyone who experiences this problem should first investigate if there is a firewall blocking your traffic between server and your client. Don’t expect that 35621, 35622, 35623, 55413, 55414 and 55415 are the only ports to open.

Than again, this is just after I have sniffed the network for a little wile and found out that the client communicates with different ports to the server. I try to keep you posted.

Chris

3

Hi

i think by opening 30000-65000 you did open all the ports one side would use when contacting the other side (dynamic port range), when all you really needed was opening 1-3 port on the other side.

Some ports are incoming some outgoing.

Note that you can only open the ports TO the server; that would be the equivalent of running in “internet mode”

4

Hi Orogor, i dit open the suggested ports and it didn’t work. The question is why do I see traffic every 50 seconds from ports 41000 to 53000? and from 37000 to 59000, lots of traffic between client and server. If the suggested ports would work, there shouldn’t be any traffic around these ports. So if I close the port range 30000 65000 and only open the suggested ports, on de client side, nothing works.

5

Also concern on this one (urbackupserver: Failed binding socket to port 35623. Another instance of this application may already be active and bound to this port)
Encountered this issue when I add an Ubuntu client - No Paths to Backup Configured

Had someone knows why?

Thanks in advance.

6

Finally solved the issue. the server was pointing te a non existing DNS. When setting is to the new name it worked instantly.

Thanx for all of your help.

7

Ryan,

This means your service is probably already running. So if you check again you get this messages that another instance is already running. For your directories, you have to enter them manually. Do this by typing urbackupclientctl add-backupdir -d /your dir you want to backup.
Do this for all directories you like to backup. You can check if they are configured correctly by running urbackupclientctl list-backupdirs.

c.