Hi,

I just posted another topic regarding firewall rules, but this is a separate problem.

My network comes under attack from hackers outside my network trying to penetrate (sending SIP based messages to try and access my PBX and make free calls, so far unsuccessfully I might add).

When I'm under attack I get a constant stream of between 500-600k of data sent continuously for about 8 hours. WAY below the max of my ADSL connection. However these attacks completely stop my access to the internet. I get DNS entry errors and in general the whole thing just slows down to a crawl and I get web pages just timing out.

Given that my router regularly manages about 4-5meg in downloading data I really can't understand why 500-600k would have such a major impact.

Can anyone shed some light on my problem please?

Thanks in advance
Iain

maybe the router processor is being overloaded by having to cope with rejecting the traffic leaving no capacity to serve dns requests etc.

perhaps you could used forced dns settings on the router/clients to take that load off?

Try turning on / off the DoS Defense - UDP flood defense - that can give the appearance of internet access failing cos it can't resolve DNS.
Part of a bigger problem though - you really need a filter rule to lock down access to 5060 UDP so the brute force attack stops.

Will do.

Thanks
Iain