# SFTP fails with packet loss



## c00kie (Mar 7, 2016)

Hi

My SFTP file transfer tunnel suddenly stopped working from my home today:


```
Command:   open "user@222.333.444.56" 2222
Command:   Pass: ***************
Error:   Authentication failed.
Error:   Critical error: Could not connect to server
```

I'm in the UK with my ISP being Virgin media. I had up until today been transferring (SFTP ing) files from my home to a server in London. Today they fail to reach the destination server though.  I spoke to support at WP Engine and they said:



> We have already established that your connection attempts aren't reaching your server over SFTP, and we have also discovered that there is complete packet loss at a node between a virgin media device and 213.152.245.54



https://static.livechatinc.com/2819642/O3HOV598KX/0c6b0ca24c43864e60eba53480ffc34f/ssh_.jpg


From the trace you can see the problem node where my packets drop out. Is there any way (software) that my packets can find a path which avoids the problem node and thus reach the server?


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## SirDice (Mar 7, 2016)

SirDice said:


> From the trace you can see the problem node where my packets drop out. Is there any way (software) that my packets can find a path which avoids the problem node and thus reach the server?


That's the ISP's job. There's nothing you can do locally that will suddenly route traffic in a different direction. You simply do not have that kind of control.


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## c00kie (Mar 7, 2016)

Are my ISP able to track this faulty node?


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## SirDice (Mar 7, 2016)

It's probably a connection of one of their peering partners. There's nothing you can do about it in any case.


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## c00kie (Mar 7, 2016)

SirDice said:


> It's probably a connection of one of their peering partners. There's nothing you can do about it in any case.


Will it resolve itself? Only I work from home and without the tunnel I kinda can't do my job at all.


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## kpa (Mar 7, 2016)

Since you have made a service contract with your ISP they are obliged to fix or at least try to fix any problems in the connection that might occur.


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## SirDice (Mar 7, 2016)

Yes, but they might be depending on one or more peering partners, that in turn are depending on other peering partners, etc. The ISP may not be able to do anything about it.

OP: You need to realize the internet isn't a "single" entity. It's actually just a large collection of independent networks that are connected through peering contracts. Each network has it's own company that runs "their" bit of the network. Any one of those can have problems.


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## c00kie (Mar 7, 2016)

SirDice said:


> OP: You need to realize the internet isn't a "single" entity. It's actually just a large collection of independent networks that are connected through peering contracts. Each network has it's own company that runs "their" bit of the network. Any one of those can have problems.


 OK, thanks for that Sir Dice. Nice introduction into peering also.


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