PPPoE client with ADSL modem in Bridge mode

RouterOS General
1

Hi!

I have one very strange problem with my RB750 router.

That’s my network topology picture:

I have ADSL modem 10.0.0.1/24 (in Bridged mode) connected to Ether1 of RB750 10.0.0.2/24
LAN Address of my router is 192.168.9.1/24. Clients are receiving address through DHCP 192.168.9.30-40/24

If Mikrotik router acts as PPPoE client to my Internet provider ping to any web site becomes >300ms. If i disconnect RB750 and use as PPPoE client my PC or ADSL modem, ping in this configuration is <60ms to any web site.

I have played with MTU/MRU parameters a lot. Also I have changed TCP MSS to prevent packets fragmentation.

I found some similar posts over this forum but those solutions not suitable for me.

That’s my configuration:
IP Addresses:

[admin@MikroTik] > /ip address print detail
Flags: X - disabled, I - invalid, D - dynamic 
 0   address=192.168.9.1/24 network=192.168.9.0 interface=ether2-Rkeeper-Podval 
     actual-interface=ether2-Rkeeper-Podval 

 1   address=192.168.31.2/24 network=192.168.31.0 interface=ether4-Wireless actual-interface=ether4-Wireless 

 2   address=10.0.0.2/24 network=10.0.0.0 interface=ether1-gateway actual-interface=ether1-gateway 

 3 D address=31.163.66.31/32 network=80.71.208.138 interface=U-tel actual-interface=U-tel 

 4 D address=192.168.9.1/32 network=192.168.9.100 interface=GH-L2TP actual-interface=GH-L2TP

Routiong:

[admin@MikroTik] >> /ip route print detail     
Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 0 ADS  dst-address=0.0.0.0/0 gateway=80.71.208.138 gateway-status=80.71.208.138 reachable U-tel distance=1 
        scope=30 target-scope=10 

 1 ADC  dst-address=10.0.0.0/24 pref-src=10.0.0.2 gateway=ether1-gateway 
        gateway-status=ether1-gateway reachable distance=0 scope=10 

 2 ADC  dst-address=80.71.208.138/32 pref-src=31.163.66.31 gateway=U-tel gateway-status=U-tel reachable 
        distance=0 scope=10 

 3 A S  dst-address=192.168.1.0/24 gateway=192.168.9.100 gateway-status=192.168.9.100 reachable GH-L2TP 
        distance=1 scope=30 target-scope=10 

 4 ADC  dst-address=192.168.9.0/24 pref-src=192.168.9.1 gateway=ether2-Rkeeper-Podval 
        gateway-status=ether2-Rkeeper-Podval reachable distance=0 scope=10 

 5 A S  dst-address=192.168.9.2/32 gateway=ether4-Wireless gateway-status=ether4-Wireless reachable distance=1 
        scope=30 target-scope=10 

 6 ADC  dst-address=192.168.9.100/32 pref-src=192.168.9.1 gateway=GH-L2TP gateway-status=GH-L2TP reachable 
        distance=0 scope=10 

 7 A S  dst-address=192.168.10.0/24 gateway=192.168.9.100 gateway-status=192.168.9.100 reachable GH-L2TP 
        distance=1 scope=30 target-scope=10 

 8 ADC  dst-address=192.168.31.0/24 pref-src=192.168.31.2 gateway=ether4-Wireless 
        gateway-status=ether4-Wireless reachable distance=0 scope=10

Interfaces:

[admin@MikroTik] >> /interface print                        
Flags: D - dynamic, X - disabled, R - running, S - slave 
 #     NAME                                                            TYPE               MTU L2MTU  MAX-L2MTU
 0  R  ;;; ADSL Modem 10.0.0.1    Login:*****    Pass:*****
       ether1-gateway                                                  ether             1500  1526
 1  R  ether2-Rkeeper-Podval                                           ether             1500  1524       1524
 2  R  ether3-RKeeper                                                  ether             1500  1524       1524
 3  R  ;;; AP IP 192.168.31.1 Login: ****** Pass:*******
       ether4-Wireless                                                 ether             1500  1524       1524
 4  R  ether5-Admin_PC                                                 ether             1500  1524       1524
 5  R  U-tel                                                           pppoe-out         1460
 6  R  GH-L2TP                                                         l2tp-out          1460

Comment: Ether1-Gateway - WAN to ADSL modem; Ether2,3,5 - Users PC’s; Ether4 - Hotspot AP; U-tel - PPPoE client to my Internet provider; GH-L2TP - VPN to central office.

Firewall:

[admin@MikroTik] >> /ip firewal export         
# jun/26/2011 02:05:20 by RouterOS 5.5
# software id = 827Q-BFKD
#
/ip firewall connection tracking
set enabled=yes generic-timeout=10m icmp-timeout=10s tcp-close-timeout=10s tcp-close-wait-timeout=10s \
    tcp-established-timeout=1d tcp-fin-wait-timeout=10s tcp-last-ack-timeout=10s tcp-syn-received-timeout=5s \
    tcp-syn-sent-timeout=5s tcp-syncookie=no tcp-time-wait-timeout=10s udp-stream-timeout=3m udp-timeout=10s
/ip firewall filter
add action=accept chain=input disabled=no dst-port=8291 in-interface=U-tel protocol=tcp
add action=accept chain=input comment="default configuration" disabled=no protocol=icmp
add action=accept chain=input comment="default configuration" connection-state=established disabled=no \
    in-interface=U-tel
add action=accept chain=input comment="default configuration" connection-state=related disabled=no \
    in-interface=U-tel
add action=drop chain=input comment="default configuration" disabled=no in-interface=U-tel
/ip firewall nat
add action=masquerade chain=srcnat comment="Ranevskaya local users" disabled=no out-interface=U-tel \
    src-address=192.168.9.37
add action=masquerade chain=srcnat comment="Ranevskaya Hotspot users" disabled=no out-interface=U-tel \
    src-address=192.168.31.0/24
add action=masquerade chain=srcnat disabled=no dst-address=10.0.0.1 out-interface=ether1-gateway
add action=masquerade chain=srcnat disabled=no dst-address=192.168.31.1 out-interface=ether4-Wireless
/ip firewall service-port
set ftp disabled=no ports=21
set tftp disabled=no ports=69
set irc disabled=no ports=6667
set h323 disabled=no
set sip disabled=no ports=5060,5061
set pptp disabled=no

Part of my PPPoE log:

Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:47 pppoe,debug,packet ether1-gateway: rcvd PADO from 00:18:18:B3:40:6C
Jun/24/2011 18:00:47 pppoe,debug,packet     session-id=0x0000
Jun/24/2011 18:00:47 pppoe,debug,packet     vendor-specific=00 00 0d e9 01 25 54 55 4d 45 4e 2d 41 47 47 30 34 35 2d 44 53 4c 2d 33 20 61 74 6d 20 31 2f 31 2f 31 32 2f 33 35 3a 38 2e 33 35 02 00
Jun/24/2011 18:00:47 pppoe,debug,packet     host-uniq=0x1c2
Jun/24/2011 18:00:47 pppoe,debug,packet     service-name=
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-name=tmn-mtts-bras-1
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-cookie=b1 5b b8 70 27 7d ef 08 98 fe a8 b6 1f 47 ff 58
Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:47 pppoe,debug,packet ether1-gateway: rcvd PADO from 00:18:18:ED:7F:24
Jun/24/2011 18:00:47 pppoe,debug,packet     session-id=0x0000
Jun/24/2011 18:00:47 pppoe,debug,packet     vendor-specific=00 00 0d e9 01 25 54 55 4d 45 4e 2d 41 47 47 30 34 35 2d 44 53 4c 2d 33 20 61 74 6d 20 31 2f 31 2f 31 32 2f 33 35 3a 38 2e 33 35 02 00
Jun/24/2011 18:00:47 pppoe,debug,packet     host-uniq=0x1c2
Jun/24/2011 18:00:47 pppoe,debug,packet     service-name=
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-name=tmn-mtts-bras-2
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-cookie=5a 0b ec e7 cd ad ae 46 a4 ad 50 be 2c 86 50 d1
Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:47 pppoe,debug,packet ether1-gateway: rcvd PADO from 00:18:18:B3:40:3C
Jun/24/2011 18:00:47 pppoe,debug,packet     session-id=0x0000
Jun/24/2011 18:00:47 pppoe,debug,packet     vendor-specific=00 00 0d e9 01 25 54 55 4d 45 4e 2d 41 47 47 30 34 35 2d 44 53 4c 2d 33 20 61 74 6d 20 31 2f 31 2f 31 32 2f 33 35 3a 38 2e 33 35 02 00
Jun/24/2011 18:00:47 pppoe,debug,packet     host-uniq=0x1c2
Jun/24/2011 18:00:47 pppoe,debug,packet     service-name=
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-name=tmn-mtts-bras-1
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-cookie=b1 5b b8 70 27 7d ef 08 98 fe a8 b6 1f 47 ff 58
Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:47 pppoe,debug,packet ether1-gateway: rcvd PADO from 00:18:18:ED:7F:84
Jun/24/2011 18:00:47 pppoe,debug,packet     session-id=0x0000
Jun/24/2011 18:00:47 pppoe,debug,packet     vendor-specific=00 00 0d e9 01 25 54 55 4d 45 4e 2d 41 47 47 30 34 35 2d 44 53 4c 2d 33 20 61 74 6d 20 31 2f 31 2f 31 32 2f 33 35 3a 38 2e 33 35 02 00
Jun/24/2011 18:00:47 pppoe,debug,packet     host-uniq=0x1c2
Jun/24/2011 18:00:47 pppoe,debug,packet     service-name=
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-name=tmn-mtts-bras-2
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-cookie=5a 0b ec e7 cd ad ae 46 a4 ad 50 be 2c 86 50 d1
Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:47 pppoe,debug,packet ether1-gateway: rcvd PADO from 00:18:18:ED:7F:54
Jun/24/2011 18:00:47 pppoe,debug,packet     session-id=0x0000
Jun/24/2011 18:00:47 pppoe,debug,packet     vendor-specific=00 00 0d e9 01 25 54 55 4d 45 4e 2d 41 47 47 30 34 35 2d 44 53 4c 2d 33 20 61 74 6d 20 31 2f 31 2f 31 32 2f 33 35 3a 38 2e 33 35 02 00
Jun/24/2011 18:00:47 pppoe,debug,packet     host-uniq=0x1c2
Jun/24/2011 18:00:47 pppoe,debug,packet     service-name=
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-name=tmn-mtts-bras-2
Jun/24/2011 18:00:47 pppoe,debug,packet     ac-cookie=5a 0b ec e7 cd ad ae 46 a4 ad 50 be 2c 86 50 d1
Jun/24/2011 18:00:47 pppoe,debug ether1-gateway: received PADO with unknown host-uniq, dropping
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet  U-tel: rcvd LCP EchoReq id=0xf
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet     <magic 0x8c34ab2c>
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet      02 2d 2c c8
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet  U-tel: sent LCP EchoRep id=0xf
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet     <magic 0x22d2cc8>
Jun/24/2011 18:00:56 pppoe,ppp,debug,packet      02 2d 2c c8
Jun/24/2011 18:01:06 pppoe,ppp,debug,packet  U-tel: rcvd LCP EchoReq id=0x10

What does it mean: “received PADO with unknown host-uniq, dropping”??

BR and thanks in advance.

I bought new ADSL modem and installed new RB750 router. The problem only in specific settings of Mikrotik router.

2

Does sound like MTU problem. In profile for PPPoE client, set Change TCP MSS to yes. This will let mikrotik dynamical create rules to correct to best MTU. Should solve problem

3

I did it, but it has not solved my problem. I’m pinging different web sites with 32 kb packets. That’s very small packet for fragmentation.
As temporary solution I use PPPoE client in ADSL modem and doing double NAT. Up to today this solution works, but today after lunch problem appears again.

4

Can’t be MTU then. Can’t think of any other possible reason except the routing that change.

5 A S dst-address=192.168.9.2/32 gateway=ether4-Wireless gateway-status=ether4-Wireless reachable distance=1
scope=30 target-scope=10

Perhaps give the gateway an ip above and then set your modem as bridge and give PPPoE client name as gateway like you did above for your internet route.

5

I have had the same odd issues with rb750’s. My fix that works for me is to not use ether1 for DSL PPPoE, move it to any other port and it starts working.

6

That’s amazing, but it works!

To lunchboxrts: Thank you for solution. We have to inform Mikrotik guys about this bug.