Connection forcibly closed by remote host

KB ID: 1781
Product: Veeam Backup & Replication
Version: 6.x, 7.x, 8.x, 9.x
Last Modified: 2016-03-15
KB Languages: ES


While a job is processing, a job might intermittently fail while sending data from the source proxy to the target proxy/repository server with:
<   744> srv| ERR |Server session thread has failed.
<   744> srv| >>  |An existing connection was forcibly closed by the remote host


This is related to a networking issue between the servers. These errors are most common when going across a WAN network, however can occasionally happen locally as well.


Typically this issue is related to packet loss somewhere on the network between the two servers. There are some utilities to test the line, however involving the ISP or networking team is typically helpful.

Some common tools typically recommended for testing are Iperf as it can give quite a bit of information about the network connection and Wireshark.

Another possible issue could be related to the Microsoft tcp/ip stack. In very rare instances, the following registry key has been used successfully when the network was not experiencing any issues:
Open regedit and navigate to the following location:
Create a dword (32 bit) value:
Leave Value set to 0 to disable this feature

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