Re: Penetrating an outbound firewall

[Wyatt, T. Rob]

Title: Penetrating an outbound firewall

Doug,

 

We are using direct MQ connections with firewall rules as specified in MA86

(http://www-3.ibm.com/software/integration/support/supportpacs/individual/supportpacs/ma86.pdf).

 

This has been working fine for us except that servers with dual NICs or virtual IP addresses (our Veritas clusters), the socket would sometimes bind to a different address under MQ pre-5.3 and be blocked by the firewall.  Prior to 5.3 we had to set up rules for the physical AND virtual addresses since the binding was unspecified.  The LOCALADDR field has really simplified things.  We have tried setting up rules for entire subnets but have since switched to using a set of rules for each point-to-point connection.  Although there are more rules, there are less surprises when you change one.

 

Might I also suggest that you run a listener (not inetd) for external traffic that is different from your internal traffic.  This way, you can shut down the external connection without impacting your internal network.  If you have multiple business partners connecting to the same QMgr, run a different listener for each.  Then you can disable one without impacting the others.

 

If you are really security conscious, run the listeners under a low-privileged ID.  For example, if you have connections to XYZ Corp and ABC Corp, you can create UserIDs xyz and abc and put them into groups xyz and abc, respectively.  Then start listeners under each ID.  This will allow you to set up authorizations on the queues such that traffic from ABC and XYZ cannot end up on each other's queues or, worse yet, on your Command Queue.  Every time I bring this up, people always reply that you can accomplish the same thing with an exit or MCAUSER.  My answer to that is that you cannot restrict traffic to a specific channel.  For example, if you define XYZ.RCVR with MCAUSER('xyz'), there is nothing to prevent ABC Corp from connecting to it.  For that matter, there is nothing to prevent ABC Corp from connecting to SYSTEM.DEF.SVRCONN or any other channel unless you run exits on ALL of them or use SSL on ALL of them.  Running the listeners under low-privileged IDs allows you to lock down a specific path from the firewall all the way down to specific queues.

 

Regards,

-- T.Rob

-----Original Message-----
From: Pierson, Doug (ITD) [mailto:[EMAIL PROTECTED]
Sent: Friday, September 05, 2003 10:30 AM
To: [EMAIL PROTECTED]
Subject: Penetrating an outbound firewall

Hi MQers,

Does anyone have any experience with sending MQ messages outbound through a firewall that restricts outbound traffic?  The traffic needs to be delivered to numerous destination servers.  Are you using MQ-IPT?  If so, are you using multiple ports to define multiple routes and sending the traffic to IPT instances deployed at each of the target servers?  Or, is all of your traffic sent to a single IPT instance outside of the firewall using a single route?  From there, queue name resolution can be used to direct it to the true destination server with the messages in MQ protocol. 

The goal of the firewall administrator is to restrict us to minimal port usage.  We see the restriction to a single port using IPT to be to costly in terms of performance.  The traffic volume is significant.  I'm also aware of MQ5.3's introduction of the LOCLADDR channel attribute to restrict outbound traffic to a single port or range of ports. 

Any comments or feedback would be much appreciated.

Thanks,
Doug Pierson