Cannot connect to VaultOS daemon - "Failed to connect to client" (4045913)

Title: Cannot connect to VaultOS daemon - "Failed to connect to client"
Date: 01/02/07
NV Version: All
OS Version: All
Application version: N/A
Plugin version: VaultOS ver 4


Description:

This FAQ describes the failure to connect to a client booted into VaultOS when that client has multiple Network Interface Cards (NICs). If the client only has one NIC then this document is unlikely to be of assistance.


Symptoms:

On a Netvault:Backup client with multiple NICs, after booting into VaultOS and configuring the NICs it is impossible to connect to the VaultOS daemon on any of the IP addresses you have configured. Consequently it is not possible to perform an Offline backup or a restore of the client.

This issue is "known as ARP flux, this can lead to the possibly puzzling effect that an IP migrates non-deterministically through multiple link layer addresses. It's important to understand that ARP flux typically only affects hosts which have multiple physical connections to the same medium or broadcast domain".

This link contains the text above and also a detailed analysis.

http://linux-ip.net/html/ether-arp.html#ether-arp-flux

In simpler terms, assume a machine has multiple connections to the same Ethernet segment, and has unique IPs assigned to each interface. A peculiar feature of linux is its willingness to respond to ARP requests for any IP bound to any interface. This can lead to ARP flux, a situation where a given IP is sometimes accessed on one MAC address and sometimes another.

There is a workaround for this behaviour:

1. On the server you wish to boot into VaultOS, physically disconnect all but one of the NICs connecting it to the network.
2. Boot into VaultOS as normal and configure all the NICs to have unique IP addresses.
3. Use Ctrl-C to "break out" of the daemon and gain access to the command line.
4. Use "ifconfig -a" to identify the interface names of all the ports.

[root@jango EMEA]# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0F:1F:68:B3:D6
inet addr:10.44.236.63 Bcast:10.44.239.255 Mask:255.255.252.0
inet6 addr: fe80::20f:1fff:fe68:b3d6/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:172217037 errors:0 dropped:0 overruns:0 frame:0
TX packets:506961806 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2371741934 (2261.8 Mb) TX bytes:2160565357 (2060.4 Mb)
Interrupt:50

eth1 Link encap:Ethernet HWaddr 00:0F:1F:68:B3:D7
inet addr:10.144.90.63 Bcast:10.144.90.255 Mask:255.255.255.0
inet6 addr: fe80::20f:1fff:fe68:b3d7/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:75794 errors:0 dropped:0 overruns:0 frame:0
TX packets:38837 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:29076852 (27.7 Mb) TX bytes:4842862 (4.6 Mb)
Interrupt:58

In the example above the interface names are "eth0" and "eth1".
5. Step through and use each interface name in turn with the following command:
ping -I
6. Identify the interface that passes the ping test (the only NIC connected).
7. Disable all the disconnected ports using:
ifconfig down
8. Execute "/bin/drdaemon" to run the VaultOS daemon.
9. Return to the Netvault:Backup server and note that you can add any one of the multiple IP addresses previously configured as they're all allocated to the one and only NIC connected.


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