![]() SNAT actions are reusable IP address translation rules, e.g. In Fireware you have SNAT actions that are configured separately from the filter rule. We normally change this setting, so no direct client to client calls are allowed and all calls go client-server-client, what makes the rest of the setup simple and easy. If you have a complex network, this can get painful ti set up and maintain. By default many servers allow direct client to client calls. There may be another issue with VOIP, that depends on the settings on your server. This can be easily solved by using a VPN connection towards your VOIP provider, if your firewall or router doesn't support some kind of SIP ALG.īut today most companies have a VOIP server on premise, so this is not really a problem. So you would have a problem, if your VOIP server was located at your provider and your clients would connect to that server over a NATed connection. No NAT, no problems - and packet filters can do the work.Īs soon as NAT is involved, you need something, that will alter the addresses in the VOIP traffic. When talking about VOIP traffic (to stay on topic), you have NAT issues, only when an address translation occurs between the server and the client. Proxies are completely different and get actively involved with the payload. Today there is much more inspection into filtered traffic, than it used to be, because of IPS and Application Control, but still packet filters don't alter the the traffic that passes them. When you create a new rule, you directly choose between proxies and filters. In WatchGuard's Fireware, there is no hiding about what is a proxy and what is a packet FILTER. These communication problems happen primarily with Dynamic NAT, while Static NAT (used mostly for server connectivity) has less issues. ![]() Solution: There is no workaround for these limitations at this time. The only exception is if the session is initiated by an external Internet client that is not behind a NAT device. ISA Server does not have a SIP application filter at this time to handle such traffic. Instant text messaging from an internal client to an external client can go out through Web proxy.Īudio, video, and whiteboard features use SIP/SIMPLE. This avoids NAT issues that arise when an external client needs the IP address of the internal client. Presence and instant message is essentially a client/server application, where the server mediates the communication between the two clients. Problem: Not all Live Communications Server functionality works through ISA Server 2004.Ĭommunication between two clients on the same side of the ISA Server computer should work in a simple internal network configuration. Live Communications Server Has Limited Functionality through ISA Server Relevant part of the article quoted below Live Communications Server used SIP and it became a problem. Troubleshooting Unsupported Configurations The article was for ISA2004 but it continued to be a problem all the way to TMG2010. SIP being the example here, but was true for any complex protocol that carries connection information inside the payload where the NAT process is left "unaware" of it and hence cannot manage the connection properly. This is a link to the material using ISA Server as an example to show the issue with complex protocols. People from the product team back then even admit to that to us (the MVPs), but never changed the documentation or the wording in the GUI. ![]() Even MS does in the ISA/TMG product when they refer to Application Layer Filters which are actually Application Layer "proxys". I've noticed also that on Watchguard there is a SIP ALG which is equivalent to a Cisco Fixup Protocol, but I think that just facilitates opening of ports, not prioritizing traffic.I am saying that Watchguard does that in how they use terminology in their documentation. ![]() I can do that, but I'd like to investigate further before we go that route. Problem is that users complain of call quality issues.Īt the moment I have setup 'Traffic Management' which uses a firewall rule and allows you to allocate/dedicate bandwidth, so I've set aside 512Kbps (10 users at site, maybe 6 calls active at once top) so this should be totally overkill.Ĩx8 says that if I can't disable SPI on the firewall, then they recommend a second firewall/gateway that doesn't use SPI, and point all phones to it. We are using Virtual Office solution from 8x8 which is a hosted SIP PBX solution. We have a site which has a 10Mb (up and down) circuit using a Watchguard x330 running 11.6.1 software. ![]()
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