I hate to reply to my own reply but... I meant third ethernet card, not second.
Geoff
Sent from my BlackBerry wireless handheld.
-----Original Message----- From: gjgowey@tmo.blackberry.net
Date: Thu, 13 Sep 2007 01:01:20 To:"CentOS mailing list" centos@centos.org Subject: Re: [CentOS] ASTERISK BOX behind a filewall
Why not put a second ethernet card in the ISA connected directly to the asterix server and have all inbound and outbound sip calls through it? You could then preserve the IP addresses for both your internal and external addresses. You wouldn't even have to nat to the asterix box since the ISA server could handle the routing and obviously if the source or dest is an internal IP then the packet gets sent to the internal interface and vice versa.
Geoff
Sent from my BlackBerry wireless handheld.
-----Original Message----- From: "Ross S. W. Walker" rwalker@medallion.com
Date: Wed, 12 Sep 2007 20:46:39 To:"CentOS mailing list" centos@centos.org Subject: RE: [CentOS] ASTERISK BOX behind a filewall
gjgowey@tmo.blackberry.net wrote:
What nat box are you running? Cable/DSL modem, Cisco router or firewall, or just a plain old home gateway?
Geoff
Well I had initially done it on CentOS, but then moved it to Microsoft ISA as managing both a CentOS and an ISA was becoming a PITA and I liked how the ISA integrated with AD. Yeah I got GNU gatekeeper to run on ISA in gateway mode... Much easier to do on CentOS though.
This is on a corporate network with 2 T1 Internet links.
Ross S. W. Walker wrote:
Feizhou wrote:
Ross S. W. Walker wrote:
Feizhou wrote:
asterisk <-> nat <-> nat <-> sip client = big pain in the neck.
I have never managed to get this to work. Getting the below was trouble enough. Forget about trying to get an asterisk box behind a nat to work with clients outside.
asterisk <-> nat <-> sip client.
Yes, you will need a specific SIP iptables filter for this to work from behind a firewall.
Getting it to work with a firewall is not a problem...it is getting the thing to work with a natting firewall that is the problem. If one end is natted, you can still do some tricks to get it to work but if both ends are natted, forget it.
Well that was the idea behind the ipfilter stuff. It will change the IPs in the protocol stream to compensate for the NAT.
It looks like there is a netfilter sip conntrack module.
I face the same problem trying to do H.323 behind a NAT'd
firewall.
Man, I stopped playing with netmeeting and gnomemeeting quite some time ago while waiting for ekiga to be available to support my video...only that you cannot compile the thing on Centos 4 without some major surgery.
Well, no it isn't for Netmeeting or Gnomemeeting, but for gatewaying our internal Polycom conferencing system to our outside bridging service. When it comes to video conferencing SIP is still in it's infancy.
I know of an H.323 filter, but haven't explored SIP as we aren't running any SIP application here yet.
Another possibility would be a SIP proxy installed on the firewall, but it is not as secure as a filter.
asterisk IS a sip proxy.
Yes, well what I was hinting at was a dumbed-down install of asterisk installed ON the firewall that would be responsible for handing off calls coming in to and out of the network from/to another larger asterisk system.
You still have to setup the sip configuration to handle that. Not much dumb downing on that aspect.
Well yes it's going to need some config, it won't need to know the full config because it is just going to do a full hand-off to the internal asterisk server for DID (does sip use DIDs?) routing.
That is the setup I had to do with GNU gatekeeper and H.323 since at the time I wasn't able to get the ipfilter h.323 filter to work properly with my Polycom system.
Ugh. Is that good luck with the sip conntrack module then?
Well, no actually you will probably have better luck then me because the module was probably written for asterisk behind a firewall. I was trying to get a proprietary Polycom system to work which is a little different.
-Ross
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gjgowey@tmo.blackberry.net wrote:
I hate to reply to my own reply but... I meant third ethernet card, not second.
gjgowey@tmo.blackberry.net wrote:
Why not put a second ethernet card in the ISA connected directly to the asterix server and have all inbound and outbound sip calls through it? You could then preserve the IP addresses for both your internal and external addresses. You wouldn't even have to nat to the asterix box since the ISA server could handle the routing and obviously if the source or dest is an internal IP then the packet gets sent to the internal interface and vice versa.
Damn top-posting is killing the thread, you may want to try the gmail client for the BB. It's getting a little OT now so let me add:
Well actually I am using GNU Gk as I'm still on H.323 not SIP, but same thing really (besides being a completely different protocol).
I would have put it in the DMZ, but for this application it didn't really pay to have a whole other box, the internal GNU Gk is in a VM. I suppose I could have created a vlan to the VM and put that in the DMZ, but vlans with shared VM ports requires 802.1q support on the VM guests and it just keeps getting more and more complex from there.
-Ross
-----Original Message----- From: "Ross S. W. Walker" rwalker@medallion.com
Date: Wed, 12 Sep 2007 20:46:39 To:"CentOS mailing list" centos@centos.org Subject: RE: [CentOS] ASTERISK BOX behind a filewall
gjgowey@tmo.blackberry.net wrote:
What nat box are you running? Cable/DSL modem, Cisco router or firewall, or just a plain old home gateway?
Geoff
Well I had initially done it on CentOS, but then moved it to Microsoft ISA as managing both a CentOS and an ISA was becoming a PITA and I liked how the ISA integrated with AD. Yeah I got GNU gatekeeper to run on ISA in gateway mode... Much easier to do on CentOS though.
This is on a corporate network with 2 T1 Internet links.
<snip old convo>
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gjgowey＠tmo.blackberry.net -
Ross S. W. Walker