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Chris Snape

SR520 Issue with ADSL connection

Hi Guys,

Need your expertise on this one. I have a Secure Router 520 with the ADSL of POTS WAN link for my company Head Office Broadband connection.

I have got it all working with one live IP address using a Loopback0 Interface.

Anyway, my issue is that overnight sometimes I find that, although the ADSL is still sync'd, my ICMP test returns only a 75% success. If I reload the router the problem is resolved but, obviously, this is not a solution.

I have tried a consumer Netgear product and it seems to be fine with this (!)

I have attached my current config for you guys to scan over and see if there is something missing.

If not the only other way I could fix this is to perform a scheduled reload at 6am every morning. If there any way of making this happen automatically without me having to type it in every day?

Thanks for any help. I would hate to have to restire the Cisco box in favour of a consumer product.


Chris Snape


Hi Chris,

The following is my understanding of your problem... please let me know if I have understood it correctly...

You have an SR520 and you have set it up as attached. And for a while all seems fine.

Then randomly late into the night you see a 25% ping drops...

If the above is correct, please answer the following for me:

1. What ip address are you trying to ping when you are tesing this and from where?


     For example - Are you pinging the WAN ip from the outside or the internet from the inside?

2. Do you see it after a specific period of time (the drops?) or do you believe it is sporadic?

You should not have to reload the router everyday morning... Lets try and find out what is happening here.

I am reviewing your config right now... a single glance did not reveal anything out of place...

I'll post another reply if I find something specific.

Thanks for the reply.

According to my ISP they can see the problems initiating around 4am on the nights it happens. It does not happen every night but a pattern as not emerged. they have had me do the usual broadband checks including using new cables, the master socket on the phone line and trying a different router. Unfortunately I could not get the other router (the netgear) to fail overnight - hence my post.

1. What ip address are you trying to ping when you are tesing this and from where?

I am pinging from my PC on the Lan side of the device to

(Can't ping from the device due to Access list)

2. Do you see it after a specific period of time (the drops?) or do you believe it is sporadic?

I would say that is reply is sporadic as I might get 5 replies then a timeout, sometimes 1 reply etc.

Thanks in advance.


Chris Snape

Hmm... This is a fascinating issue...

Could you post for me the output of

1. show interface dialer0

2. show interface ATM0

I want to check if there are any issues at the interface level.

Also can we try pinging another ip address instead of just to isolate that its not that the bbc server getting overloaded or not replying ping.

You could use one of the public dns server like or

At the time when the packets are dropping... try pinging different addresses to see whether this makes a difference

Thanks for your thoughts on this.

Further investigation with my ISP shows that the ADSL line is still dropping with the Netgear router but, somehow, the Netgear router is sorting itself out. Whereas the Cisco box is not and needs manual reload.

So it does look like the main reason for the issue lies with the phone line. But if I can't get my ISP or BT to get the matter looked at (as it works with the Netgear) then I might still have to retire the Cisco box

The only other solution would be to try and auto-reboot the Cisco box every day at 6am just to guarantee working broadband by the time the first members of staff arrive.

Any ideas on this as a fall back position?


Chris Snape

Sorry to bring this one back up again but it looks like it IS the Cisco box afterall.

How do I know? Well, I now have three identical boxes all running on seperate ADSL connections in my Head office and this morning they were all offline!

They all showed intermittant drops of the Virtual-Access2 interfaces throughout the night with two of the three not even bringing it back up. the other was up but with the same packet loss as previously mentioned!

Should I be looking to upgrade the firmware? Is there an ADSL setting I am missing form the config I originally supplied?

Need help on this please as I am having to reload them every morning. Currently having to remember to scedule the night before.

My ISP is showing outages in the night but thinks it must be environmental or the hardware setup. PRevious Speedtouch reouters worked fine on two of the ADSL lines so it can;'t be the lines.



Chris Snape