The PPPOE up and down continuously

[Trung Minh]

Hi all,

I have a network as picture attached file.

Recently, sometime i always received message from firewall notification that port3(p3 connect to 20Mb) up and down continuosly in few seconds.(someday happened, someday not happened).

I informed to IPS and they always confirmed that all related their network(signal + cable) are fine.

I also checked my hardware status are Ok.

Now, i do not know how to check  or which tools can use to check its caused by my network devices or by IPS

Any one can help me this?

I very appreciate.

Regards,

[kcnajaf]

Hi Trung,

Is the router 2821 managed by you? If so please paste the configuration. Also which firewall are you using? Could you please provide the interface configuration for port3?

Regards

Najaf

[Trung Minh]

Hi Najaf,

I am glad to hear you.

I also attached "router config"  file here.

I using fotigate as firewall, and this FW will get IP from my Router is gateway

Mean: such as Router's IP: 10.10.10.1, and FW is : 10.10.10.2

Best regards,

[kcnajaf]

Hi Trung,

Sorry to say that im little confused now. Your subject heading  shows "PPPOE up and down continuously". And the details below shows "from firewall notification that port3 (p3 connect to 20Mb) up and down continuosly" So the question is

1) Whether the dialer interface on the router is going down or is the port (Fas 1/0) which connect to the firewall is going down?

Regards

Najaf

[Trung Minh]

Hi Najaf,

I am getting message notification from my FW said that port3(p3 on FW connect to fa1/0 on Router) up and down continuously in few seconds.

That why i can not detected it caused by my network devices or IPS (router using pppoe protocol).

Although, i checked all related to hardware status are fine.

Do you know have any tool can check issue in this case?

How i can check if the ISP said a lie or not?

Thank you.

[kcnajaf]

Hi Trung,

That make sence. Please check what is the speed and duplex configured on your foritgate? I can see from your router config that from the router end it is 100 full. So it should the same as well on the firewall end as well rather than auto negotiation.

More likely this wouldn't be issue due to ppoe connection. Still you can check the status of ppoe connection failure with below command on the router.

show vpdn history failure

Hope above command wil be able to give some details of link flaps on ppoe.

Regards

Najaf

[Trung Minh]

Hi Najaf,

When i used "show vpdn history failure" it show that "% VPDN user failure table is empty".

Its mean something wrong on my network devices not IPS?

Do you have any tools to monitoring network devices? Could you please show me?

Thanks so much,

[kcnajaf]

Hi Trung,

You are right..This shows there is no problem from you ISP end. So as suspected before the issue is with your end devices? Did you check the speed and duplex on the fortigate? You can check that using diagnose hardware deviceinfo nic on fortigate CLI.Also check on the logs on the router to see if you see any interface down logs at the same time when you see the logs on your firewall.

With regards to monitoring tools there all lot os tools avilable for network monitoring. Solarwinds would be a good choice to monitor the up down status of the network devices.

Regards

Najaf

[Trung Minh]

Hi Najaf,

I checked on fotigate and show the speed and duplex is the same on Router configuration.

May be something missed configure on firewall, i have to find out...

I thinks Solarwinds is very powerful and complicated

I like the free tool which can install on linux to monitoring network device, do you have any idea for this?

Thank you so much for willing to help.

Regards,