added Groups and users:

groupadd -g 3555 exfel, 5478 exfl_jet

adduser --home /home/username --uid xxx --gid 3555 username

added all or some of them to the group 5478 exfl_jet   "adduser username exfl_jet"

Install:

apt-get install krb5-user libpam-krb5

change the "/etc/krb5.conf"

put in:

[libdefaults]
        default_realm = DESY.DE
        clockskew = 300
        v4_instance_resolve = true
        default_etypes = des-cbc-crc
        default_etypes_des = des-cbc-crc
        krb4_get_tickets = true
        v4_name_convert = {
                host = {
                        rcmd = host
                        ftp  = ftp
                        pop  = pop
                        ldap = ldap
                        imap = imap
                        ldapserver = ldapserver
                }
        }

[realms]
        DESY.DE = {
                kdc = netra32.desy.de
                kdc = netra33.desy.de
                kdc = netra34.desy.de
                admin_server = netra32.desy.de
                default_domain = desy.de
        }
        WIN.DESY.DE = {
                krb4_get_tickets = false
                kdc = adc11.win.desy.de
                kdc = adc12.win.desy.de
                kdc = adc13.win.desy.de
                kdc = adc14.win.desy.de
                kdc = adc15.win.desy.de
                admin_server = adc11.win.desy.de
                default_domain = WIN.DESY.DE
                v4_instance_convert = {
                        desy = desy.de
                        win.desy = win.desy.de
                }
        }
        NAF.DESY.DE = {
                kdc = tcdc1.naf.desy.de
                kdc = tcdc2.naf.desy.de
                kdc = tcdc3.naf.desy.de
                default_domain = naf.desy.de
        }
        IFH.DE = {
                kdc = kdc1.ifh.de
                kdc = kdc2.ifh.de
                kdc = kdc3.ifh.de
                admin_server = kdc1.ifh.de
                default_domain = ifh.de
        }

[domain_realm]
        .desy.de = DESY.DE
        .win.desy.de = WIN.DESY.DE
        .naf.desy.de = NAF.DESY.DE
        .ifh.de = IFH.DE

[appdefaults]

sshd = {
        ticket_lifetime = 86400
        renew_lifetime = 172800
        forwardable = true
        krb4_convert = true
        afs_cells = desy.de
        validate = false
        proxiable = false
        retain_after_close = false
        minimum_uid = 0
}

pam = {
        ticket_lifetime = 86400
        renew_lifetime = 172800
        forwardable = true
        krb4_convert = true
        afs_cells = desy.de
        validate = false
        proxiable = false
        retain_after_close = false
        minimum_uid = 0
}

kinit = {
        ticket_lifetime = 86400
        renew_lifetime = 172800
        forwardable = true
        krb4_convert = true
        afs_cells = desy.de
        validate = false
        proxiable = false
}