import re


def is_valid_server_name(server):
    """
    Validate server name if it is in the form of '1234@server-name'

    Parameters
    ----------
    server : str
        Server name

    Returns
    -------
    bool
    """
    m = re.match(r'^[1-9][0-9]*@[a-zA-Z0-9-.]+$', server)
    return True if m else False