Ssh_exchange_identification: read: Connection reset by peer

I've got an odd and urgent problem. I'm trying to connect to a vendor's ftp site. I have tried connecting from multiple places. I've found that I cannot connect from my production server1 but I can connect from my testserver1 which are both housed in the same datacenter. I can also connect from the backup server located in another datacenter. I cannot connect from my office computer, but I can connect from my home computer. Up until about 2 days ago, I was able to connect on all of these boxes.

sftp -v username@host

Connecting to host...
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to host [**.**.**.**] port 22.
debug1: Connection established.
debug1: identity file /home/***/.ssh/id_rsa type -1
debug1: identity file /home/***/.ssh/id_dsa type -1
debug1: loaded 2 keys
ssh_exchange_identification: read: Connection reset by peer
Couldn't read packet: Connection reset by peer

I'm able to successfully ping the host from all boxes. I've run traceroutes for all of them as well and it doesn't appear to be cutting off anywhere. I've been on the phone with the vendors network admin and she says that despite it saying connection established on my end, she doesn't see me connecting anywhere in the logs.

I've tried browsing some other similar questions but I'm not having any luck. If anyone can point me in the right direction or shed any light on the situation it would be greatly appreciated. I've tried turning off the firewall on my office machine and still no luck. We're not using keys so I'm not sure why they are loading. Where it is being reset is where it prompts me for my password on the machines where it works.

I'm also more than happy to call the vendor's customer service if it's something on their end.

Update
adding -vvv gave me the line:
debug2: ssh_connect: needpriv 0
between the applying options and connecting to host lines.