“Read from socket failed: Connection reset by peer” message when using ssh client with certain internet providers

Question

I normally use MOBAXterm to SSH into my work pc, but when I use my gf's internet connection, it works for only a little while before giving me the above error message.

It also happens when I ssh into other external machines and it also happens when I use putty. I already implemented all the in-build steps MOBAXterm offers that could potentially fix this problem.

My suspicion is that it's related to the internet connection cutting out temporarily, but I don't see why that should be such an issue.

Any advice would be appreciated.

Answer 1

Two possibilities here, the nefarious and the irritating. If you know how to sniff traffic, a pcap dump of the session dying would be extremely useful. Grab it using the stable version of Wireshark .

The nefarious possibility

Traffic shaping. SSH can be used to tunnel VPN traffic. If the ISP is difficult about it (more likely if they're a big ISP) they could happily send RSTs to long-lived sessions.

The irritating possibility

Sketchy home router. If the NAT table is too full, the router's memory is overloaded, or there's a bug in the firmware, the NAT table could drop sessions which would cause what you describe.

Solutions

Try mosh . It uses SSH for session setup, then its own protocol over UDP for the actual session. It's UDP-based so there's no TCP connection to RST, and mosh is designed to survive a nuclear strike. It doesn't even care if your IP address changes mid session.

The problem is likely to be solved using mosh - even if it's the home router, mosh's session continuity will mask the NAT table resetting.

If you want to replace the home router (for example if the same thing is happening to other protocols), and you can get the authentication details for the Internet connection, try swapping it out for another one - preferably a recent high-end SOHO model.

If the connection presents as Ethernet (for example a cable modem, like Virgin) then my standard known-good is the TP-Link Archer C7 .

If the connection is DSL-based (copper phone line, or BT fibre), you'll also want a 1-port VDSL (for fibre) or ADSL/ADSL2+ (for copper) modem capable of bridge mode. You'll need this in addition to the Ethernet router.

For VDSL, I'd probably recommend the ZyXEL VMG1312-B . For ADSL/ADSL2+ I'd suggest the ZyXEL P660-R .