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Context:

Our company has several remote workers. One of them is a fair ways away (1500 miles). All of the remote workers have Windows workstations and connect via the Cisco AnyConnect VPN system, which we host from an ASA at our headquarters. We operate a lot of Linux virtual machines (ESXi) at our headquarters.

We recently hired a new developer. Unlike other remote workers, he needs to do more than just samba-shared resource access; he needs to work on the Linux VMs. So, we told him to connect to the VPN and use PuTTY.

Probably not important, but I'll mention it anyway: this developer runs a local VM on his computer via VMWare Player (latest version), which shares his computer's internet connection (using "Bridged" networking). This VM can't connect to resources at headquarters (because the VPN client runs on the hosting computer, not on the VM), but has no problems connecting to the internet for other purposes.

Problem:

His access to internal VMs is really laggy. Like, "type a sentence and wait a second for the keystrokes to finish getting printed to your terminal" laggy.

What I've Tried:

At first, I thought that our VPN was just slow, and we hadn't noticed it yet because nobody used it for the same kind of work as the new developer. So I logged in to the VPN from home (6mi from headquarters) and did some work via PuTTY, and it was fine. My colleagues and other developers confirmed that everything they did over the VPN was just as responsive as it was at headquarters. So the issue is localized to this one guy.

Next, I told the new developer to check his latency via ping and tracert. The highest latency I saw for him was 80ms, usually around 60. Those numbers didn't seem preventative, so straight-up network latency didn't seem to be a problem

Then, we figured that it might be a latency/traffic issue with his ISP (our headquarters has very fast, low-latency internet connectivity). We switched him to a new local internet provider (there aren't many choices; he's in the geographic middle of nowhere in Montana, US) that guaranteed fast, low-latency links. No dice; still laggy.

Question: What might be causing this latency issue? His ping is fine, and no other VPN users have this trouble, but using a remote terminal is still massively difficult for this one employee.

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Has he tried a different SSH client? It could be something funky with the terminal emulation in PuTTY. –  MDMarra Sep 28 '12 at 19:52
    
Latency is only one of the factors that can create network performance issues. I would take a look at packet loss between his end and the office. –  joeqwerty Sep 28 '12 at 19:53
    
How? I'm not familiar with testing that. I can do a continuous ping, and it doesn't show any dropped ICMP messages, but I imagine that's very different from TCP packet loss checking. –  Zac B Sep 28 '12 at 19:59
    
Try iperf - sourceforge.net/projects/iperf –  joeqwerty Sep 28 '12 at 20:22
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