5.1p1 doesn't work, 5.0p1 works fine

[Damien Miller]

On Wed, 27 Aug 2008, Dan wrote:

> This is the cause of the problem! I can connect fine to my APC UPS now
> this is commented out. With the router, right after the password is
> entered, there's this error message:
>
> PTY allocation request failed on channel 0
>
> Then I get the router prompt, and everything is fine from then on.
>
> I suspect this issue will come up more often as more people use 5.1p1
> with vendor-supplied sshd servers in various pieces of hardware.

You should complain to your vendor, they are violating the specification.
>From rfc4254, section 4 "Global requests":

>   If the recipient does not recognize or support the request, it simply
>   responds with SSH_MSG_REQUEST_FAILURE.

What server identification does your UPS report? Look for a line like
the following in your "ssh -v" output:

debug1: Remote protocol version 1.99, remote software version OpenSSH_5.1

-d