Junos OS

Hello all,

Recently I came accross a dynamically created VLAN interface (demux0) which prevents the customer from retrieving his IP address after a short interruption of the PPPoE session.

I tried to clear the demux0 interface by doing the following:

user@core3# run show subscribers | match 1265    
demux0.1073900204    1265                                                             default:default      

[edit]
user@core3# run clear auto-configuration interfaces demux0.1073900204 
error: No interface session for logical interface demux0.1073900204, session 5471525

This usually works, but I can't help the customer reconnecting to our MX80 router.

I tried everything what could possibly be related to this matter, but no luck so far.

Does anyone have a secret trick I can use here?

Beeelze

hi Beeelzebub,

You can configure below knob under auto-configure config, which will clear the interface once subscriber logouts..

# set interfaces <Interface-name> auto-configure remove-when-no-subscribers

Hi Vishruth,

Thanks for your answer.

However, the "remove-when-no-subscriber" statement is something we configure on all Access interfaces toward customers.

Would perhaps enabling and disabling that statement do something?

I can't take any unnecessary risks as there are many other customers connected to that physical interface.

Beeelze

Hi Beeelze,

There should not be any impact..

Hi Vishruth,

Tried disabling / enabling the remove-when-no-subscriber statement.

But the demux0 interface is still there.

Anything else I could try besides a reboot?

Beeelze

Hi Beeelze,

Can you share the config of the interface and dynamic porfile used.

Hi Vishruth,

beeelze@core-nkh-03# show interfaces xe-0/0/3 auto-configure 
stacked-vlan-ranges {
    dynamic-profile DEMUX-QinQ {
        accept pppoe;
        ranges {
            /* Inner VLAN 7 Voice */
            any,7-7;
            /* Inner VLAN 6 Data */
            any,6-6;
            any,5-5;
        }
    }
}
vlan-ranges {
    dynamic-profile DYNINTF-VLAN-DHCP-INET-KPN {
        accept [ dhcp-v4 dhcp-v6 ];
        ranges {
            1000-1024;
            1026-1041;
            1043-1046;
            1049-1053;
            1056-1066;
            1068-1071;
            1076-1078;
            1082-1082;
            1084-1084;
            1086-1090;
            1092-1093;
            1097-1099;
            1102-1104;
            1107-1107;
            1115-1117;
            1127-1127;
        }
    }
    dynamic-profile DEMUX-Q {
        accept pppoe;
        ranges {
            1025-1025;
            1042-1042;
            1047-1048;
            1054-1055;
            1067-1067;
            1072-1075;
            1079-1081;
            1083-1083;
            1085-1085;
            1091-1091;
            1094-1096;
            1100-1101;
            1105-1106;
            1108-1114;                  
            1118-1126;
            1128-4000;
        }
    }
}
remove-when-no-subscribers;

beeelze@core-nkh-03# show dynamic-profiles DEMUX-Q   
interfaces {
    demux0 {
        unit "$junos-interface-unit" {
            demux-source inet;
            proxy-arp;
            vlan-id "$junos-vlan-id";
            demux-options {
                underlying-interface "$junos-interface-ifd-name";
            }
            family inet {
                unnumbered-address lo0.0 preferred-source-address <IPv4 loopback>;
            }
            family inet6 {
                unnumbered-address lo0.0 preferred-source-address <IPv6 loopback>;
            }
            family pppoe {
                duplicate-protection;
                dynamic-profile PPPoE-SUBSCRIBER;
            }
        }
    }
}

beeelze@core-nkh-03# show dynamic-profiles PPPoE-SUBSCRIBER 
predefined-variable-defaults {
    inactive: input-filter police-unlimited;
    inactive: output-filter police-unlimited;
}
routing-instances {
    "$junos-routing-instance" {
        interface "$junos-interface-name";
        routing-options {
            access {
                route $junos-framed-route-ip-address-prefix next-hop "$junos-framed-route-nexthop";
            }
            access-internal {
                route $junos-subscriber-ip-address {
                    qualified-next-hop "$junos-interface-name";
                }
            }
        }
    }
}
interfaces {
    pp0 {
        unit "$junos-interface-unit" {
            ppp-options {
                pap;
                authentication [ pap chap ];
                mru 1492;
                mtu 1492;
            }
            pppoe-options {
                underlying-interface "$junos-underlying-interface";
                server;
            }
            keepalives interval 60;
            family inet {
                filter {
                    input "$junos-input-filter";
                    output "$junos-output-filter";
                }
                unnumbered-address "$junos-loopback-interface";
            }
            family inet6 {
                address $junos-ipv6-address;
            }
        }
    }
}

VLAN in question is 1265 as stated before.

May i know the version you're using?

clear auto-configuration interfaces demux0

Is the above command not working?

Regards,

Rahul 

Hi rnayar,

Version:

beeelze@core-nkh-03# run show version

Hostname: core-nkh-03

Model: mx80

Junos: 14.2R7-S9

clear auto-configuration interfaces demux0 does not work indeed, see below attempt:

beeelze@core-nkh-03# run show subscribers | match 1265 
demux0.1073900204    1265                                                             default:default      

[edit]
beeelze@core-nkh-03# run clear auto-configuration interfaces demux0.1073900204 
error: No interface session for logical interface demux0.1073900204, session 5471525

Beeelze

Hi,

Please upgrade the release to 15.1R7 or 16.1R7. 14.2 is not recommended for subscriber-management. This will create unnecessary SDB related issues.

Please try below HIDDEN command.

jtac@jtac-mx960dc-r2036# run dynamic-configuration session delete session-id X

Regards,

Rahul

Hi rnayar,

That hidden command did the trick!

Thank you very much!

Beeelze

Hi all,

When i use command "run dynamic-configuration session delete session-id X" then when i try to renew back the dhcp then it cannot get ip address. If i reboot the vMX then it will back to normal.

Any other command that can use to clear the subsriber instead using command above?

Thanks and appreciate any feedback

Hello kronicklez,

Please create a new topic, and post your question there - your context is most likely different, and the solution may be different as well. If you have DHCP local server, the following command should do the trick:

user@mx> clear dhcp server binding ?
Possible completions:
  <address>            IP address or MAC address or Session Id of DHCP client binding
  <interfaces-vlan>    Interface VLAN-ID/SVLAN-ID on which to clear bindings
  <interfaces-wildcard>  Interfaces to clear bindings on (can be '*' wildcard)
  all                  Clear all bindings
  dual-stack           Clear dual stack bindings
  interface            Name of interface on which to clear bindings
  logical-system       Name of logical system
  routing-instance     Name of routing instance
  tenant               Name of tenant

Best regards,

Sergii

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Hi,

Do not use CLI “dynamic-configuration session delete session-id XXXX” to delete subscriber session. This knob can cause unexpected behaviours  & it’s strictly not be used in production environment thus its hidden command.

In case if subscriber session is not being cleared using primary command “clear network-access aaa subscriber username xxx' if the suscriber is authenticated (other than PPPoE, you can have DHCP authenticated subscriber as well).

Now in your case of DHCP, clear the dhcp client binding as follows:

 clear dhcp server binding x.x.x.x routing-instance (if any)

and in case of dhcp relay, use the follow:

clear dhcp relay binding x.x.x.x routing-instance (if any)

please log a new thread/post to know more gracefull CLI knob to clear a session.