When the MX router acts as BRAS and runs a Tomcat version (15.1R4 or later) of JunOS, the subscribers (dhcp or pppoe) cannot telnet or ssh the MX router.

The Subscriber interface does not support telnet or ssh from Tomcat versions. Junos OS is working as designed.

The following workaround can be used to resolve this issue:

Create logical-systems and connect it with the default system by using lts interface. Then the subscriber can telnet this logical-system's IP.

In the following example configuration, note that a customer must set the interfac/IP according to the actual situation:

user@MX480-re0# show 
logical-systems {
    mgt {
        interfaces {
            lt-2/0/0 {
                unit 1 {
                    encapsulation ethernet;
                    peer-unit 0;
                    family inet {
                        address 10.0.0.3/31; <----Sub can telnet/ssh this ip
                    }
                }
            }
        }
        routing-options {
            static {
                route 0.0.0.0/0 next-hop 10.0.0.2;
            }
        }
    }
}
chassis {
    fpc 2 {
        pic 0 {
            tunnel-services;
        }
    }
}
interfaces {
    lt-2/0/0 {
        unit 0 {
            encapsulation ethernet;
            peer-unit 1;
            family inet {
                address 10.0.0.2/31;
            }
        }
    }
}