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Re: RV120W doesn't allow browsing


Employee David Hornstein
Currently Being Moderated
25. Aug 24, 2010 7:38 AM in response to: Jason Mack
Re: RV120W ROUTER/FIREWALL "cannot display the webpage"

Hi Jason et al..

i believe the technician are now aware of a UDP issue on the Rv120W.

The internal discussions on the issue from R&D and development  seems to be;

1.       By default on RV120W there is a UDP Flood attack check which limits 25 UDP Connections Per Client in one instance, i.e at a particular time instance a PC behind this router can establish only 25 UDP Transactions, if we exceed router drops UDP Packets.

2.       We have a script that sends dns lookup queries at a very high rate than the router clears the UDP entries, this way we build up the UDP entry table in the router(i.e 25 entries)

3.       Once 25 limit is reached we are unable to resolve further DNS queries, using the script or using the browser.

4.       In the real world scenarios there might be one PC behind the router and open a website where all the items on the webpage are linked to different website, if you open this kind of website it may have links to more that 25 different website and clog the routers UDP table for that particular PC and user might not be able to resolve further DNS queries and unable to browse any new websites. This unability to browse happens until the UDP entries on the router time outs  and are cleared.

5.       This limit of 25 is because of the feature called Block UDP flood on the router which is enabled by default.

6.       Once we disable the block UDP Flood, router does not check for 25 UDP Connections limit and dns resolution is continuous without a break.

This is what a customers in the field might be seeing interruptions in DNS resolutions and website browse failed.

Some customers explicitly talked about DNS failures.

Jason I can see you have placed a service call, so hopefully CCORAL who posted on the 15 August should be helping you.

So Folks, If the Technician  deem the problem not a hardware issue requiring RMA, the technician will escalate the call to our Level 2 folks in Irvine, probably CCORAL.  You will get assistance to resolve this issue.

The Small Business Support center, should be aware of the problem. Please feel free to show them this posting, i am willing to chat with them to get the ball rolling.

So again, if you have not done so already,  please contact the SBSC  and place a service request and keep a copy of that number they give you as a reference (you may need it). My appologies for the inconvenience you have all had.


Dave Hornstein

Small Business, Channel Systems Engineer

Cisco  - Research Triangle Park.  USA


Re: RV120W doesn't allow browsing

How did you make out with this? Did this setting take care of your problems?

Frequent Contributor

Re: RV120W doesn't allow browsing

I switched to a RV042 and WAP-54G combo.  Didn't make any sense to keep messing with it.



Re: RV120W doesn't allow browsing

The UDP setting helped my case anyways. There is also rumor of a 'beta' firmware from Cisco that solves several issues with these routers, but you'll have to call Cisco support to get it. I havn't called so I don't have it and thus cannot comment on that.