how to check expiry of ssh keys

[subiksha]

I have heard that there is no expiration for ssh keys. But still one of my client to whom i have given my public ssh key says that my ssh key is expiring on so and so date. I have never set an option to expiration date. I haev also not used passphrase while key generation. How can I check the expiration date. If this is set at client side, I am supposed to provide him a new key. Do I need to delete the old public key from authorized_key file because some other clients are using old key only? Please let me know how to check the expiration date of my ssh public key and how to delete the key from authorized_key file?

[GNU-Fan]

Hi,

I think maybe you confuse key with certificate.
They are often used together but not exactly the same.