I just purchased a Unitrends appliance, and it sits in my data center backing up 4 servers without any issues at all. However, I'm having a heck of time getting it to run backups over my IPSEC VPN's to two remote offices. After a seemingly random amount of time, all remote office servers will fail with a "Failed to send summary" event log. Sonicwalls reside on both ends. Here's what I've found:
1) Intrusion Prevention Services was definitely a problem. It would detect the Unitrends agent NAT'ing from some random port to 1743, and drop the packet immediately at the firewall in the data center. The Unitrends would detect a network disconnect, an event log would toss up, and the entire process would halt. Disabling the IPS services fixed the problems that I could reproduce.
2) I still get intermittent errors regarding "incomplete backup data", and event logs about "Failure to send summary". This implies a network issue (I think), but my network has no noticeable outage. No logs about a disconnect. No disconnects with a random large file transfer. Even my old Barracuda 390 never had this issue.
3) I've tried changing the MTU on both ends, to give room for the encrypted packet header. No dice.
4) I've tried increasing the TCP timeout for TCP 1743 and 1745, as per a suggestion in another thread.
5) I've tried disabling dead-peer detection. No dice.
6) I've manually added policies to allow all traffic between my servers and the Unitrends, even with the help of Sonicwall tech support. Didn't help.
7) I've toyed with VPN tunnel settings, like keep-alive and advanced routing, but that doesn't seem to work.
8) On the Unitrends, I've reinstalled the client. I've tried trusted/non-trusted credentials. I don't see many options at all to change how the backups are run - just replication between appliances.
I'm at my wits end here; been fighting with this for two days straight. Has anyone ever successfully implemented Unitrends backups over a VPN between two Sonicwall appliances? Any recommendations?
It just seems so strange to me that, even if the VPN was experiencing intermittent connectivity issues, the Unitrends agent can't reconnect and try again in some way. Maybe I'm missing something.