On Thu, 25 Jan 2001, Ghosh, Vikram wrote:
> Date: Thu, 25 Jan 2001 17:22:06 +0800
> From: "Ghosh, Vikram" <[EMAIL PROTECTED]>
> To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
> Subject: YAHOO and MSN Messenger
>
> Hi
>
> Could somebody please tell me what TCP ports does Yahoo and MSN messenger
> work on as I need to block these ports using access lists on a CIsco Router.
For Yahoo Messenger I use the following ruls for ipchains :
A bit of explanation, in case you can't figure out :
# -s <source>
# -d destination
# -p <IP protocol>
# -j <policy>
# -l - log packets which match this rule
# -A <chainname> - append rule to this chain of rules
#
# Block Yahoo Messenger
#
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 1/0 5050
$IPCHAINS -A output -p udp -j REJECT -l -s 1/0 -d 1/0 5050
# cbs.yahoo.com
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.202.58
$IPCHAINS -A output -p udp -j REJECT -l -s 1/0 -d 204.71.202.58
# The next hosts are cs[1-9].msg.yahoo.com
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.202.119
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.200.55
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 216.115.107.146
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.200.57
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.201.100
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.202.59
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.202.58
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 204.71.200.54
$IPCHAINS -A output -p tcp -j REJECT -l -s 1/0 -d 216.115.105.57
#
# Block Yahoo Messenger
#
$IPCHAINS -A input -p tcp -j REJECT -l -s 1/0 5050 -d 1/0
$IPCHAINS -A input -p udp -j REJECT -l -s 1/0 5050 -d 1/0
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.202.58
$IPCHAINS -A input -p udp -j REJECT -l -d 1/0 -s 204.71.202.58
# The next hosts are cs[1-9].msg.yahoo.com
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.202.119
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.200.55
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 216.115.107.146
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.200.57
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.201.100
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.202.59
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.202.58
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 204.71.200.54
$IPCHAINS -A input -p tcp -j REJECT -l -d 1/0 -s 216.115.105.57
I think it is working, users aren't using yahoo messenger anymore.
(they use some other messengers :)) )
____________________________________
Catalin Braica
[EMAIL PROTECTED]
Tel: 409-452-4161 Work: 405-141-3496
http://www.edulib.ro/~catalin/
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