On 02/20/2018 09:33 AM, H wrote: > On 02/19/2018 10:09 PM, Marcelo Ricardo Leitner wrote: >> On Mon, Feb 12, 2018 at 08:05:18PM -0500, H wrote: >> ... >>> Not sure if I am reading your reply correctly but I should clarify >>> that I have problems when running naked ssh to the server, when I >>> run ssh to the same server but over the VPN connection (that goes >>> via third server) everything is flawless. >>> >>> I should also explain that: >>> >>> - I am on a workstation (located in the US), ssh-ing into server 1 >>> (located in the US). >>> >>> - From server 1 I use scp to transfer large files from server 2 >>> (located in Europe) to server 1 (in the US). >>> >>> The above randomly disconnects. >> You have two ssh sessions here. AFAICT, it's the first one >> (workstation->server 1) that randomly disconnects, right? >> >>> However, when: >>> >>> - I use a VPN connection to server 3 (also located in Europe). >>> >>> - From the same workstation as above, do exactly as above, >>> connections are rock-solid. >> It would seem to me that something between your workstation and server >> 1 is possibly mishandling TCP options (being it sack, timestamps or >> both). Is there a router or a firewall in between? >> >> Try doing a traffic capture between both and see why it hangs. If >> you're hesitant to post the binary traffic capture, post the text >> version of it with anonymized IP addresses. Just please be sure to >> disable ssh protocol so it would include TCP details on it then. >> >> Marcelo > Let's reduce the problem to a simpler case: the workstation running CentOS 7 is behind a router, behind the same router is the server running CentOS 6. For various reasons, I access the server via its external IP address, not the local one. Access is via ssh. > > When using straight ssh, the connection times out after random times, always less than 20 minutes or so, though, with the error message "packet_write_wait: broken pipe", not the common "write failed: broken pipe". > > However, when I am in a ssh session on a VPN connection (which terminates in an outside server far away from my network), the ssh connection does /not/ time out. > > Further, accessing the same server as first mentioned, in the identical fashion, from another computer running CentOS 6, I never encounter the "packet_write_wait" error and disconnection. > > My conclusion is thus that this is not a router issue but could conceivable be a bug in CentOS 7. I am also ruling out a cable issue or a physical network card issue since the VPN connection is stable. > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos No messages in secure or message logs.