I looked on the feature navigator, and not all IOS images for the 2950 have an integrated SSH integrated client, even though it may have an SSH server function.
It shows that the crypto version of IOS for that platform DOES include an ssh client, and the non-crypto version doesn NOT have an ssh integrated client.
Now if your IOS does have the ssh client, and is trying the connection, it is possible that the client (built into the switch) only supports SSH v1, or only some some of the older algorithms that are not being accepted by the destination SSH sever.
You may want to verify that SSH 1 connections are accepted by the target, as well as perhaps try different options of encryption or hashing from your client.
Below is from a router that supports SSH2 client functions:
-c Select encryption algorithm
-l Log in using this user name
-m Select HMAC algorithm
-o Specify options
-p Connect to this port
-v Specify SSH Protocol Version
WORD IP address or hostname of a remote system
R1#ssh -c ?
3des triple des
SSHv2 only cipher list:
aes128-cbc AES 128 bits
aes192-cbc AES 192 bits
aes256-cbc AES 256 bits