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New Member

Blocking Yahoo Instant messenger

I have added an deny statement for the TCP and UDP port 5050 but, people can still connect by using port 80. Any suggestions on blocking this IM?

  • Other Security Subjects
4 REPLIES
New Member

Re: Blocking Yahoo Instant messenger

You are not going to be able to block Yahoo Instant messenger or any of the latest instant messenging programs by port. They pretty much all have the ability to scan for and use any available port if the default port is not available. The only way to block them is to sit down and do nslookups for all of the possible IP addresses and block it by IP address.

HTH

Bob Staaf

Southern Web Services

Orlando, Fl

New Member

Re: Blocking Yahoo Instant messenger

Bob is correct. I have blocked AIM, MSN Messenger, Yahoo Messenger, etc. this way.

New Member

Re: Blocking Yahoo Instant messenger

You cannot block any of the instant messenger programs today by port. They all have the ability scan for and use an open port. What I have done is install and use all of these programs and watch the logs to get the IP addresses they all use. I don't have my list handy but, I will try and post it tonight. I block all of the popular ones, AIM, Yahoo, MS and ICQ. There are quite a few addresses and all any of them have to do is move the server to another IP and you have to start the game all over again.

New Member

Re: Blocking Yahoo Instant messenger

As my understanding, tracing all the IP addresses is time-consuming. I wish to have all the addresses for well-known Instant Messager from you. Can I? You can send them through my email address mwwong@advantis.com.my. Thanks.

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