From: Vinu (vinupeter@gmail.com)
Date: Fri Jan 25 2008 - 05:35:27 ARST
Thanks for that......it is really helpful
On Jan 24, 2008 10:39 PM, EDL <r.s.cciestudy@gmail.com> wrote:
> Results from a quick search on google.com
> +++++++++++++++++++++++++++++++++
>
> Blocking Google Talk in your Organization
> Recently I had an issue of Blocking Google Talk service for the
> organization
> I work.
>
> In Google Talk Developer Info: it was told that the Google Talk service
> runs
> at url: talk.google.com at port 5222. Tracert revealed that
> talk.google.com
> points to talk.l.google.com @ 209.85.137.125.
>
> But: Blocking 209.85.137.125 at port 5222 does not block Google Talk
> service.
>
> Then I used WildPackets.com's OmniPeek Personal Edition to probe out a
> packet level analysis.
>
>
> Google Talk uses Port 80, Port 443 and Port 5223 other than Port 5222 for
> its communication purposes. Worst of all: Google Talk connects to
> 216.239.37.125, 72.14.253.125 and 72.14.217.189 other than 209.85.137.125.
> It connects to Ports 5222, 5223, 443 and 80 in all the cases.
>
> Blocking all these 4 addresses blocks Google Talk at both Browser and Talk
> Client. Note: This does not disable Google mail.
>
> Bottom line: Block access to 216.239.37.125, 72.14.253.125, 72.14.217.189
> and 209.85.137.125 on ports 80, 443, 5222 and 5223.
>
> Note1: This is one of the measures to Block Google Talk. Meebo has an
> option
> wherein one can logon to any IM network., including Google, MSN and
> Yahoo!.
> So does Kool IM, eBuddy and ILoveIM. So you got to block these sites too
> if
> you want to curb IM misuse.
>
> Note2: Geeks will get on a workaround like using an SSH Tunnel using
> puTTY,
> public proxies, TOR, etc., In order to circumvent this., so you got to use
> thirdparty traffic shapers like Akonix IM Control, Websense, etc., that
> sniff out Jabber traffic and prevent usage of proxies.
>
> Note3: If you want to Block File Transfers alone in Google Talk: Block
> Ports
> 20 and 21.
>
> Note4: This blocks Google Talk Gadget too !!!
>
> +++++++++++++++++++++++++++++++++
>
>
>
> ----- Original Message -----
> From: "Vinu" <vinupeter@gmail.com>
> To: "Cisco certification" <ccielab@groupstudy.com>
> Sent: Wednesday, January 23, 2008 10:21 AM
> Subject: How do i block google talk on a Firewall ?
>
>
> > Is there any specific port that google talk uses ? need urgent help.
> >
> > --
> > Regards,
> >
> > Vinu Peter
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
>
>
-- Regards,Vinu Peter
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