Intermittent WAN connection

Unanswered Question
Mar 12th, 2010

Good day, group.

This week I installed and configured the SA520 device on our network.  Today several members of the business have complained to me that pages will intermittently not load for them.  There's no rhyme or reason for the page - MSN start page, web banking, whatever.  A browser refresh will usually fix the page load issue.  When running a linux firewall before getting the Cisco (aka Delta) hardware installed, my users had not experienced any connectivity issues.  I'm certain it's not a problem with our fiber Internet connection.

I'm running firmware 1.1.21 with no URL filtering whatsoever.  My DNS records are pointing to OpenDNS for speedy lookups.

Any ideas or do you need to see my configuration?


I have this problem too.
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biraja Sat, 03/13/2010 - 11:54

Hi Chris,

Can you post the config and discribe a bit about the topology?

Will address this issue ASAP.



biraja Sat, 03/13/2010 - 12:19

Hi Chris,

Can you tell me what kind of WAN config you have (PPoE or DHCP or Static IP)?



clutka_cisco Mon, 03/15/2010 - 06:47
Can you post the config and discribe a bit about the topology?

Config attached.

Topology: Using a static IP address provided by my fiber ISP.  Internet traffic coming in on a dedicated VLAN 784 as provided by the ISP which terminates to a Cisco WS-2950 switch.  Through port programming, the connection traverses to the SA520 router and gets dumped back into the switch which then services the LAN connections.

Users have only noticed that the HTTP connections are not solid.  It could very well be DNS issues causing the problem.  Generally I don't get users contacting me when their streaming radio goes down so I can't tell if it's a WAN, TCP port, or DNS.  I'm simply comparing the setup I had with a Linux firewall (m0n0wall) I had set up as a temporary measure while I was waiting for the router to arrive and no one complained about the Linux setup.


Steven Smith Mon, 03/15/2010 - 10:41

Go to firewall and then to attacks.

Can you take off the check on UDP flood?

Also, on that page, try unchecking the block fragmented packets.

clutka_cisco Mon, 03/15/2010 - 10:53

Thanks for the suggestion. I've applied the "fix" and have asked the

users noticing the issues to respond back to me with feedback. I

probably won't have an update until tomorrow.


clutka_cisco Mon, 03/15/2010 - 12:06

Go to firewall and then to attacks.

Can you take off the check on UDP flood?

My user stated that she's still experiencing some issues. I'll see if

we have any DNS issues on our end but if you have any other suggestions

in the meantime, I welcome them willingly. Thanks.


Steven Smith Tue, 03/16/2010 - 13:32

Can you get a sniffer from the LAN and from the WAN when you do this?  In Administration -> Diagnostics, you can do a packet trace.

Do you have an internal DNS server?  Do you use the SA 500 as your DNS server?


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