Hi all,

I have just installed a RB750 to connect all my LAN (10.0.0.0 class) towards internet (using a Zyxel ADSL P-660H modem as gateway). Where Ether1 is connected to gateway and Ether2 is connected to my local LAN, all 3 other interfaces are not used.

I have also configured transparent webproxy and forwarding all ports 80, 81, 88, 8080 and 3128 to 8080 so all my users will be automatically forwarded to webproxy for all they requests. So in webproxy I have set filtering based on filetypes and domain name content.

In firewall I have configured proxy to be available only for my network, activated the suggested protections from web interface (all other changes I do either by Winbox or by terminal) and use Layer7 protocol to block all messengers and other traffic to 90% of computers in my LAN using access lists instead of having to input IPs one by one. Just a couple of PCs are allowed to access MSN Messenger.

The problem is since when I have installed Mikrotik, the MSN Messenger in these two PCs is continuously reconnecting every few minutes and most of time they don't even see that they're logged out, the Messenger icon shows as CONNECTED but instead people are calling (these are online support PCs) and asking us why we don't reply or why we're offline.

I have looked into forum and somewhere they suggested to change MTU from 1500 (default) to 1450 and I already tested this on the local network interface and did not give any good result. My connection is ADSL with PPPoE but the Zyxel modem handles the PPPoE connection, I just connect to this modem as a standard gateway and the RB750 doesn't do the PPPoE itself.

Looking forward to your questions and comments

Hi gerequi,

Can you post your Layer7 regex please? I think that this could be your problem because I've done the same with a RB450 and I got no problem at all.

Best Regards,
tehknox

Hi tehknox,

What is the regexp of MSN messenger? because i've blocked the messenger but in other way, which is adding users to a address list and then blocking them for 25 seconds, but that means that everything else gets blocked, not just messenger...I've tried it with layer 7 but it doesn't work for me

Have you read this article in the Wiki ? http://wiki.mikrotik.com/wiki/Drop_IM_Using_L7 This is where it all began! Use this with Layer7 and it will work pretty well. I got no problem with this at all. If you can understand how it works, then you will be able to filter almost anything on your network (study regex (regular expression) and you are good to go).

Hop this will help you!

Best Regards,
tehknox

Well,

I have setup my configuration based on the same link you mention (http://wiki.mikrotik.com/wiki/Drop_IM_Using_L7) and I have configured everything just like there. The blocking is going just fine for address lists which I mention (because I am blocking IM only to certain IPs in my network, not all of them, this is why I am using address lists in firewall)

And so the Messenger in two PCs who should be not blocked anyhow, they get disconnected every few minutes and reconnecting. This is becoming very annoying as users don't even notice the messenger being offline so they have to manually check it every 3-5 minutes. In all other IPs where the IM should be blocked it works!

Seems that the filtering is not working OK and not distinguishing correctly the IPs

I have tried so far to disable all of the firewall rules from blocking any Messenger over network and problem is still there. Later I will try to bypass RB750 and bridge LAN directly to ADSL modem...