Cannot connect to server from a Virtual Machine

Restore
1

  • UrBackup Server v2.2.11.2193 on Ubuntu 16.04 LTS

  • fresh install of Ubuntu 16.04 LTS into a VirtualBox VM

  • installed urbackup client on said VM

  • client is not seen by server

    root@vserver:/# urbackupclientctl status
    {
    “capability_bits”: 12,
    “finished_processes”: [],
    “internet_connected”: false,
    “internet_status”: “no_server”,
    “last_backup_time”: 0,
    “running_processes”: [],
    “servers”: [],
    “time_since_last_lan_connection”: 1179460
    }

Any tips?

2

What type of network connection have you configured for your VM? (Bridged Network?)

3

Yes, bridged. Both machines reply to pings.

4

and they are both in the same network, so an UDP broadcast from the client will reach the server?

5

Tried capturing UDP packets with tcpdump, this is the result:

10:06:49.198607 IP (tos 0x0, ttl 64, id 45771, offset 0, flags [DF], proto UDP (17), length 29)
	192.168.15.183.35623 > 255.255.255.255.35622: [udp sum ok] UDP, length 1
10:06:49.298680 IP (tos 0x0, ttl 64, id 14576, offset 0, flags [DF], proto UDP (17), length 36)
	192.168.15.132.35622 > 192.168.15.183.35623: [bad udp cksum 0xa0ad -> 0xfd81!] UDP, length 8
10:07:39.921399 IP (tos 0x0, ttl 64, id 58342, offset 0, flags [DF], proto UDP (17), length 29)
	192.168.15.183.35623 > 255.255.255.255.35622: [udp sum ok] UDP, length 1
10:07:40.199207 IP (tos 0x0, ttl 64, id 23291, offset 0, flags [DF], proto UDP (17), length 36)
	192.168.15.132.35622 > 192.168.15.183.35623: [bad udp cksum 0xa0ad -> 0xfd81!] UDP, length 8

After disabling TCO (tcp offloading) for TX/RX on the NIC the problem is gone

$ sudo ethtool -K eth0 tx off rx off

10:26:27.497545 IP (tos 0x0, ttl 64, id 2614, offset 0, flags [DF], proto UDP (17), length 29)
	192.168.15.183.35623 > 255.255.255.255.35622: [udp sum ok] UDP, length 1
10:26:27.910184 IP (tos 0x0, ttl 64, id 5001, offset 0, flags [DF], proto UDP (17), length 36)
	192.168.15.132.35622 > 192.168.15.183.35623: [udp sum ok] UDP, length 8

However, client still cannot connect to server

6

Does it work if you add the client IP as discovery hint? (Add client on the status page, then the lower option)