Demystify HLB and DNS Load Balancing - TechNet Gallery

Demystify HLB and DNS Load Balancing - Lync 2013 Topology with
High Availability (POOLs, DNS LB vs HLB)
© 2014, Thomas Pött, MVP Lync
Demystify HLB and DNS Load Balancing - Lync 2013 Topology with High Availability (POOLs, DNS LB vs
HLB) ......................................................................................................................................................... 1
Client-to-Server and Server-to-Server traffic high availability: ............................................................... 3
Client-to-Server .................................................................................................................................................. 3
Server-to-Server ................................................................................................................................................. 3
Lync Server Roles entitled for High Availability:...................................................................................... 3
POOL Servers ...................................................................................................................................................... 3
Director Server ............................................................................................................................................... 4
Frontend Server ............................................................................................................................................. 4
Edge Server: ................................................................................................................................................... 4
Mediation Server: .......................................................................................................................................... 4
Other Server: ...................................................................................................................................................... 4
SQL ................................................................................................................................................................. 4
File Share ....................................................................................................................................................... 4
WAC ............................................................................................................................................................... 5
Gateways ....................................................................................................................................................... 5
Lync High Availability ............................................................................................................................... 5
POOL ................................................................................................................................................................... 5
Count of servers in a pool: 1, 2 or 3+ server in a pool .................................................................................... 6
Hardware Load Balancing ............................................................................................................................. 7
DNS Load Balancing: ...................................................................................................................................... 7
Specialties ........................................................................................................................................................... 8
Edge server .................................................................................................................................................... 8
Mixed of DNS+HLB and HLB ........................................................................................................................... 8
1-Armed or 2-Armed solution: ....................................................................................................................... 8
Mediation server and gateways .................................................................................................................... 9
Resiliency: .............................................................................................................................................. 10
Backup Pool: ..................................................................................................................................................... 10
SBS/SBA: ........................................................................................................................................................... 10
Pool: ................................................................................................................................................................. 10
Technical requirements and ports for load balancing .......................................................................... 10
Certificates ....................................................................................................................................................... 10
Ports ................................................................................................................................................................. 10
External Port Settings Required for Scaled Consolidated Edge, Hardware Load Balanced: External
Interface Virtual IPs ..................................................................................................................................... 10
Firewall Summary for Scaled Consolidated Edge, Hardware Load Balanced: Internal Interface Virtual IPs 11
Director Ports and Protocols for Firewall Definitions (DNS-HLB) ................................................................ 12
Director Ports and Protocols for Firewall Definitions (HLB) ........................................................................ 13
Frontend Hardware Load Balancer Ports if Using Only Hardware Load Balancing (HLB) ............................ 13
Frontend Hardware Load Balancer Ports if Using DNS Load Balancing (DNS+HLB) .................................... 14
Source References ................................................................................................................................. 14
The most misunderstood topic in Lync is the high availability. This is regardless of server count, positioning or
DNS versus hardware load balancing.
Note:
This document is neither a sizing nor a configuration guide. You should use this document only for your
environment planning’s purposes.
In my first chapter I need to drive into the different understandings of high availability.
Client-to-Server and Server-to-Server traffic high availability:
First I need to explain some generic settings bout load balancing.
And one word before you read this article:
My personal recommended opinion is the DNS+HLB 1-armed solution, this makes trouble shooting much
more simplified and do not require so much network knowledge for the Lync admins. On the Edge server
recommend only 1-armed and purely HLB.
Client-to-Server
The only part, were the both option DNS+HLB and HLB come into place is for the Client to Server traffic ONLY.
Server-to-Server
Lync Server traffic is much different. As we setup the server first in the topology, Lync servers are aware about the
entire topology setup with in the CMS or XDS database. This source will be queried to load balance server-toserver traffic fully automatically. That’s one part we have later to consider with LB 2-armed solution.
Lync Server Roles entitled for High Availability:
Lync Server 2013 can be made high available by using redundant servers, which means we have to deploy multiple
server in an array. This array in Lync topology is named POOL. A pool can have assigned 1 up to 12 server,
regardless if we are talking about the different server roll, which are directors, frontends, mediations, group chat
or edge servers. Beside Lync server, where the Lync application is installed on, we also have several other
components, which I describe later in this passage.
Note:
You should also understand the difference between High Availability and Resiliency. Please do not mess around
with this differences
POOL Servers
All four server rolls described next are entitled for POOL based high availability.
Director Server
The incoming, general SIP requests from external and internal Clients will be redirected to its responsible Frontend
system, most likely a Pool. Authentication is part of this server too.
The Director Server host both, Lync Application and IIS for Web Services.
Frontend Server
The core component of Lync. It hosts the users and every of their responsible functions Lync offers. They also will
always have collocate the Conferencing part. Beside this, Archiving and Monitoring truly its hosted as well.
Optional, if it makes sense, the Meditation feature could be added to this system too.
Edge Server:
Lync component for external SIP related traffic. This is one of the only servers, which are not responsible for any
kind of Web Services Lync has to offer.
But what’s about this server? Well, Lync Edge Server is a standalone, Non-Domain Joined System, designed to act
as a true Application Proxy and Application Reverse Proxy.
Let me repeat some basic requirement:
You MUST have 2x NICs and 2x dedicated/ separated/ isolated Networks and the internal DNS Suffix of your
Active Directory Domain must be present, else Edge cannot work!
Mediation Server:
As described, the Meditation server can also be separated from the Frontend Server. It is responsible for
translating SIP to ISDN (also SIP Trunk), second it also doing transcoding from Lync codecs into G.711.
Other Server:
All of the server named above are pool servers, which can be configured under a single, addressable name space.
All other system Lync need to operate with are different and will have different requirements to operate in high
availability mode.
SQL
The SQL server, also called “Lync Backend” can be operated in two high availability modes. One is the well-known
cluster, where we have two SQL servers in an active-passive mode. The other option the better choice, SQL server
mirroring. Mirroring exists with two SQL server, where the primary server hosts the active database and do log
shipping of all its transaction to the second, independent SQL server. Therefor a logical independent database
copy exists.
Why this is even better than a cluster? First, we have a second database copy, independent from the other and
second, if you only operate the mirror server for Lync, you do not need to pay the SQL server license.
File Share
Lync also need file storage for several features. Here we are able to utilize the most system opportunities. We can
simply cluster the file storage, or we make use of Distributed File System (DFS) and its replication technology.
Other third party solutions as NetAPP or EMC can be used to. But you need to ensure the correct Lync
requirements are full filled.
WAC
Office Web Application (former Office Web Companion) the server rendering in Lync 2013 all Power Point
presentations into HTML5. Regarding high availability, we make use of “FARMS”, a farm are multiple WAC server
installed and joined the farm, receiving the identical configuration. Since it is a Web based service, we can load
balance this servers. The two methods are: hardware load balancing, or windows load balancing. (Note: this is the
only system, which is entitled for Windows Load Balancing)
Gateways
At last, we have the Audio transcoding and protocol changes to ISDN or others. This is for some the most complex
systems if we are talking about high availability.
Since the Gateway cannot be deployed in a Lync related pool, we need to create another kind of system
collection.
In Lync 2013 we have several components/ elements in the IP flow. Starting with the mediation server, the
mediation server has two sites and one of them is associated with the ISDN gateway. This does not mean we need
two dedicated NICs, but it is in some circumstances possible or even necessary. In between of this path, we
associate both sites with a Lync 2013 TRUNK. This are the three components involved.
Now we have to opportunity for high availability with a backup gateway (alternative gateway), the other option
native in Lync if we deploy multiple paths and the third option is a load balanced solution between the mediation
server and the gateways as bidirectional communication flow.
Lync High Availability
POOL
Every Lync pool servers are capable of both load balancing solutions, as long a supported client is used. The
supported clients are Lync 2010, Lync 2013 and the App Store, as well the mobile clients.
Before I dig into the both scenarios, lets have a quick discussion about the two relevant components in Lync.
Beside the Lync applications, we have web related services. Those service are e.g. Address Book Distribution,
Distribution Group resolution, Meet and Dialin page, or Lync Mobile Clients Autodiscover and others. We
remember the setup of our external facing systems, in our case the Reverse Proxy. Here a special mapping of the
related http port 80 and 443 is needed within the redirection process, the port mapping will be 80 -> 8080 and
443 -> 4443. Why is this so?
The Lync Web Services are running inside the IIS, due to security reasons, Lync segregates all web traffic onto
internal and external web sites. Since we have only a single IP address on the Lync servers, the only possibility is if
its using different ports. Therefore the external connections run on the Lync external site under port 8080 and
4443.
After this excurse let’s come back to the main topics. In other words, we talk about SIP, server function and web
services in Lync. All of them have to be high available. While SIP can be considered as a so call “persistent”
protocol, if we use simple load balancing mechanism like DNS Round Robin, a TCP connection will with the
“supported” Lync client always stay with its initiated Lync server. Well this is a very simple and rudimentary
explanation, but should be solvent enough for this article. I more like to high light the word “persistent”, means
continuously established IP session. Web Services in general are different. Web service must not and cannot be
persistent. This is because of the IP session will always be reestablished after an http request is finished. In Lync we
need to submit web requests on a session basis, but how this can be done, if we e.g. use a round robin process?
Each time a client would start a new request and the server is not aware that within the same session and we
would hit another server in a pool, the information stream within this session would have got lost. Therefore web
services must stick to the same server. To do this and enable the client hitting the same server again, a supporting
technology must be in place. Here we have several options, cookie based sessions or source IP address affinity.
Now, since we understand this requirements, the recommendation for hardware load balancing is clearer. In the
same way we can now understand why Windows Load Balancing cannot be used with Lync pool. Windows
load balancing is based on shared information within the WLB cluster and communicated via multi/ unicast. This is
never sufficient for the requirements of Lync.
NOTE:
Windows Load Balancing can neither be used for Web service, nor Lync application services, even due to those
services exist on the same server and cannot be separated.
Count of servers in a pool: 1, 2 or 3+ server in a pool
Very often I’m asked by other consultants: Why Microsoft recommends 3+ server in a pool.
I want to have a look what is happened to the pool with different server counts.
But this discussion is only related to Lync Frontend server pools, other pool follow the simple principals of at least
2 servers and +1 for each high availability user count. Say you have 10.000 users , so you need 2+1 Director
server, since 1 server is allowed to fail until the load cannot be handled anymore. If you add more than +1 you
increase the high availability but more related to SLAs since more server can fail.
Lync Frontend server are different, for user load and associated quorum. Truly the server to user count is quite
similar. If you have 30.000 user for a single pool, you need at least 3 server +1 or more for high availability.
What is if you say, we have only 7.000 users on a single pool?
1.
Single Frontend server in a pool
this single server is fully sufficient for 7k user and will run with this load. Also the necessary quorum is
simple, it’s a single node system equivalent to what we understand from single node clusters.
2.
Dual Frontend server
this is a working configuration, even if its not recommended. This also does not mean it would be
unsupported. BUT:
If we assign this solution, we need to keep in mind that under some circumstances we might run into
issues. Those issues are probably happened, if one server fails and the left one is restarting. In this
scenario when the server is restarted, the server is in an inconsistent state and will need up to 1 hour
before the services will have started. The Lync Frontend quorum need to be rested.
Command: Reset-CsPoolRegistrarState –ResetType QuorumLossRecovery
As we can see, if we only install a pool of Frontend servers with 2 nodes, we need to be prepared
handling cases like described.
3.
3+ more Frontend server
This is the recommended setup for high availability. If you are planning so for customers you will have
the best in class solution with all necessary automated processes and less impact during system failtures.
Disadvantage is still the cost factor, since the server license count is higher.
I will now have the look into the high availability technology required to support those setups.
Hardware Load Balancing
We identified three components, the both IIS web site and the Lync application. Therefore a full hardware load
balancing solution will cover all components for Lync. Sure the setup of HLB is a little bit more complex and
requires more port which need to be load balanced. Also the load balancer will have more load compared with a
setup of only web services. Since the Lync application do not need to off-load TLS encryption to the HLB, the
impact is quite less.
I personally prefer this way of setup due to a more clearer setup and we know also in case of issues with load
balancing, where to look for issues. The support process is straighter forward.
Other to this is, if we setup a fully load balance solution, we are able to implement 1- or 2-amred setup of load
balancers.
Note:
Another advantage of hardware load balancing is, if you need to take a pool server offline, this is purely done on
the HLB and do not require DNS changes, which also need time to be replicated.
DNS Load Balancing:
If you decide for DNS based load balancing, this setup make use of Lync application only. Due to the point we
discussed more early, even if we decide for DNS based load balancing, the web services required a hardware load
balancer.
For session based load balancing, it is a must that we have a look into the HTTPS data stream, which than require
a SSL off-load to be configured.
If we do so, the shared pool server certificate must be copied and used on the hardware load balancer.
NOTE:
Web Services must be HLB, it is necessary to change the INTERNAL and EXTERNAL Web Services to a dedicated
name. Example: PoolName: FEPOOL01.<ad fqdn>, internal Web Services: intFEPOOL01.<sip domain>, external
Web Services: extFEPOOL01.<sip domain>
Web Services External



Use TCP idle timeout of 1800 seconds
Ports 8080 and 443 for external web traffic
set cookie-based persistence on a per port basis
o Cookies must not be marked httpOnly.
o Cookies must not have an expiration time.
o Cookies must be named MS-WSMAN.
Web Services Internal



Ports 80 and 443 for internal web traffic
set source_addr persistence
Exception for internal Lync Mobile clients » use cookie persistence instead
Specialties
Regardless with load balancing solution we chose, there are still more consideration we have to take in place. I
separated this into three chapters
Generic Information Lync Mobility Services
Cookie-based persistence required for Lync Mobilityservices

Marked httpOnly, named MS-WSMAN and no expiration
Edge server
Edge pool server can also either be load balanced on hardware basis or via DNS. Important are here two points:
1.
2.
3.
If you decide for one of the both possibilities, you MUST stick to the same setup on both site of the Edge
pool. Which means, the external and the internal site (NICs) must make use of the identical process.
DNAT Load Balancing (half-NAT) for A/V Edge (external)
If you decide for DNS based load balancing you have some restrictions:
This restriction apply if the “core” server of the pool will fail.

Exchange Unified Messaging:
If EUM is deployed and Exchange 2010 prior SP1 is used, the user will have no access to their voice mail

Office 365 and Public Instant Messaging (PIC):
The communication is broken, since both systems do not support DNS load balanced Edge pool

Federation with partners with Office Communication Server 2007 / 2007 R2
The communication is broken, since both systems do not support DNS load balanced Edge pool. DNS
load balancing was not available with OCS
Mixed of DNS+HLB and HLB
Beside of the provided information for Edge servers and the internal and external site, you are entitled to make
use of both solutions with in your Lync topology.
As a simple example:
If you have a topology with 2x Edge, 2x Director and 3x Frontend servers, you can do a setup of DNS LB for the
Edge server, DNS LB+HLB for the Directors and HLB for the Frontend server.
Also this scenarios are supported
1-Armed or 2-Armed solution:
Load balancer setup can vary in two different deployment, either 1-armed or 2-armed. The difference between
both is how the IP flow has to run. While in a 1-armed solution the IP traffic will first hit the LB, than redirected
based on the LB algorism directly to the pool server. Afterwards the IP traffic is a direct communication between
the source and target.
In a 2-amred setup the IP flow is different, the source will always communicate with the LB and the LB than starts,
based on the algorism again, with the target pool server.
A specialized setup if a LB between the PSTN site of a Mediation server and its associated gateways. I will describe
this later.
Routing vs redirect
What is now this difference between a redirected and a routed setup? If we decide for the 1-armed solution, we
enable the source for a direct traffic exchange with the target and we do not need a isolated network. The setup is
more simplified compared with the 2-armed solution. Here we need the IP flow to be routed to its target.
This has a direct impact on the high availability setup we can chose. If a 2-armed is the choice, we cannot use DNS
LB, this is because we can use multiple A records in DNS pointing to the different pool servers, because we can
address them directly due to the LB with acts as a router.
PICTURE
If 2-armed only than u make use of server load analysis
Say, we decided for this option. We have a huge advantage coming from the LB. We are now able to fully control
the traffic flowing through the LB. Since the LB continuously know the amount of data routed to the target pool
server. The LB is aware of its load.
In scenarios, where we have to consider higher load on the pool, this might be the best choice, since we are able
to redirect traffic much more efficient.
Say, one pool server host a huge conference and it load is now quite high, the LB is aware of this traffic and able
to redirect other traffic to member server in this pool, which have lesser load.
Truly, this is not described in the Microsoft deployment guides, since this is comes from the networking
prospective.
NOTE:
If you are using a 2-armed solution, you cannot use DNS load balancing and you need to ensure, that server-toserver communication is possible and the HLB works for this fully transparent.
PICTURE!!!
Mediation server and gateways
The most complex setup is a load balancer in between of the Mediation server and the gateway. We have reduced
ports we are utilizing here, mostly a single port 506x. But we need to plan the Mediation server, load balancer and
gateway positioning in conjunction with the Lync TRUNK configuration. So it’s a more advanced config which
provides the highest availability and routing of call to ISDN.
PICTURE


SNAT Load Balancing (Full-NAT) for gateway/PBX side of Mediation Server Pool
Use if Gateway doesn’t support DNS LB to simplify Gateway/PBX configuration
Resiliency:
I leave this chapter a bit shorter since it should be only understood as generic knowledge. If you design Resiliency
it requires another longer article….
Backup Pool:
Some consultants try to avoid HLB balancers at the customers and recommend a two standard edition server
deployment, where the second standard server servers as a backup registrar. Sure you can consider, but this is not
a god choice and requires much more knowledge for the customer as compared to the little knowledge of HLB.
SBS/SBA:
Its really the most recommended solution, if you have branch offices with no admins and you preferable need
resiliency for VOICE.
Pool:
Assuming you have two datacenter, possibly far away from each other. Here you have the best option setting up
this both dedicated pool in a relationship, acting as backup for each other. Combined with GEO-LB this is a
solution of amazing high availability.
Technical requirements and ports for load balancing
More early I wrote an article about load balancing, you might consider this in your learning path too.
http://lyncuc.blogspot.de/2012/07/load-balancer-gateway-and-session.html
Certificates
Certificate requirements can become complex in mind of security. If you need to separate the certificates assigned
in pools, you have so many choices how to define the certs for all services. But what I want to highlight here are
the certificate for Web services.
You are able to assign each Web service an individual certificate, this means internal and external site of the IIS. If
you do so or not, you MUST be able to export the certificate to the HLB for SSL OFF-LOADING, this also requires
you to have the SAME certificate with the same private key assigned onto all pool servers.
Please note about this else you will run into serious issues.
OAuth protocol is not mentioned here, since this not an option to be load balanced. Just keep in mind, you should
have assigned the same OAuth certificate on all pool server as well.
Ports
External Port Settings Required for Scaled Consolidated Edge, Hardware Load Balanced:
External Interface Virtual IPs
The table below has been taken from Port Summary - Scaled Consolidated Edge with Hardware Load Balancers
Role/Protocol/TCP or UDP/Port
Source IP
address
Destination IP
address
XMPP Proxy service
(shares IP address
with Access Edge
service)
XMPP/TCP/5269
Any
XMPP/TCP/5269
Any
Access/SIP(TLS)/TCP/443
XMPP Proxy
service (shares IP
address with
Access Edge
service)
Any
Access/SIP(MTLS)/TCP/5061
Any
Access Edge service
public VIP address
Access/SIP(MTLS)/TCP/5061
Access Edge
service public
VIP address
Any
Federated partner
Web
Conferencing/PSOM(TLS)/TCP/443
A/V/STUN,MSTURN/UDP/3478
Any
A/V/STUN,MSTURN/TCP/443
Any
Notes
XMPP Proxy service
accepts traffic from
XMPP contacts in
defined XMPP
federations
XMPP Proxy service
sends traffic to XMPP
contacts in defined
XMPP federations
Access Edge service
public VIP address
Edge Server Web
Conferencing Edge
service public VIP
address
Edge Server A/V Edge
service public VIP
address
Edge Server A/V Edge
service public VIP
address
Client-to-server SIP
traffic for external user
access
SIP signaling, federated
and public IM
connectivity using SIP
SIP signaling, federated
and public IM
connectivity using SIP
Web Conferencing media
STUN/TURN negotiation
of candidates over
UDP/3478
STUN/TURN negotiation
of candidates over
TCP/443
Firewall Summary for Scaled Consolidated Edge, Hardware Load Balanced: Internal Interface
Virtual IPs
The table below has been taken from Port Summary - Scaled Consolidated Edge with Hardware Load Balancers
Role/Protocol/TCP or
UDP/Port
Access/SIP(MTLS)/TCP/5061
Access/SIP(MTLS)/TCP/5061
SIP/MTLS/TCP/5062
Source IP address
Any (can be defined as
Director, Director pool
virtual IP address,
Front End Server or
Front End pool virtual
IP address)
Edge Server Internal
VIP interface
Any (can be defined as
Front End Server IP
address, or Front End
pool IP address or any
Survivable Branch
Appliance or
Destination IP
address
Edge Server
Internal VIP
interface
Any (can be
defined as Director,
Director pool
virtual IP address,
Front End Server or
Front End pool
virtual IP address)
Edge Server
Internal VIP
interface
Notes
Outbound SIP traffic (from
Director, Director pool virtual
IP address, Front End Server
or Front End pool virtual IP
address)to Internal Edge VIP
Inbound SIP traffic (to
Director, Director pool virtual
IP address, Front End Server
or Front End pool virtual IP
address) from Edge Server
internal interface
Authentication of A/V users
(A/V authentication service)
from Front End Server or
Front End pool IP address or
any Survivable Branch
Appliance or Survivable
STUN/MSTURN/UDP/3478
Survivable Branch
Server using this Edge
Server)
Any
STUN/MSTURN/TCP/443
Any
STUN/MSTURN/TCP/443
Edge Server Internal
VIP interface
Branch Server using this Edge
Server
Edge Server
Internal VIP
interface
Edge Server
Internal VIP
interface
Any
Preferred path for A/V media
transfer between internal and
external users
Fallback path for A/V media
transfer between internal and
external users if UDP
communication cannot be
established, TCP is used for
file transfer and desktop
sharing
Fallback path for A/V media
transfer between internal and
external users if UDP
communication cannot be
established, TCP is used for
file transfer and desktop
sharing
Director Ports and Protocols for Firewall Definitions (DNS-HLB)
The table below has been taken from : Port Summary - Single Director
Role/Protocol/TCP or
UDP/Port
HTTP/TCP 8080
HTTPS/TCP 4443
HTTPS/TCP 444
Source IP
address
Reverse
proxy
internal
interface
Reverse
proxy
internal
interface
Director
Destination IP
address
Director
Hardware Load
Balancer VIP
Director
Hardware Load
Balancer VIP
Front End pool
or Front End
Server
Director
Hardware Load
Balancer VIP
Director
Hardware Load
Balancer VIP
Director
HTTP/TCP 80
Internal
Clients
HTTPS/TCP 443
Internal
Clients
SIP/MTLS/TCP 5061
MTLS/TCP/50001
Edge Server
internal
interface
Any
MTLS/TCP/50002
Any
Director
MTLS/TCP/50003
Any
Director
Director
Notes
Initially received by the external side of the reverse
proxy, the communication is sent on to the
Director HLB VIP and Front End Server web
services.
Initially received by the external side of the reverse
proxy, the communication is sent on to the
Director HLB VIP and Front End Server web
services.
Inter-server communication between the Director
HLB VIP and the Front End Server or Front End
Servers.
The Director provides web services to internal as
well as external clients.
The Director provides web services to internal as
well as external clients.
SIP communication from the Edge Server to the
Director, as well as the Front End Servers.
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Director Ports and Protocols for Firewall Definitions (HLB)
The table below has been taken from : Port Summary - Single Director
Role/Protocol/TCP or
UDP/Port
HTTP/TCP 8080
HTTPS/TCP 4443
HTTPS/TCP 444
Source IP
address
Reverse
proxy
internal
interface
Reverse
proxy
internal
interface
Director
Destination IP
address
Director
Hardware Load
Balancer VIP
Director
Hardware Load
Balancer VIP
HTTP/TCP 80
Internal
Clients
HTTPS/TCP 443
Internal
Clients
SIP/MTLS/TCP 5061
MTLS/TCP/50001
Edge Server
internal
interface
Any
Front End Server
or Front End
pool
Director
Hardware Load
Balancer VIP
Director
Hardware Load
Balancer VIP
Director
Hardware Load
Balancer VIP
Director
MTLS/TCP/50002
Any
Director
MTLS/TCP/50003
Any
Director
Notes
Initially received by the external side of the reverse
proxy, the communication is sent on to the
Director HLB VIP and Front End Servers web
services
Initially received by the external side of the reverse
proxy, the communication is sent on to the
Director HLB VIP and Front End Servers web
services
Inter-server communication between the Director
HLB VIP and the Front End Servers
The Director provides web services to internal as
well as external clients.
The Director provides web services to internal as
well as external clients.
SIP communication from the Edge Server to the
Director, and Front End Servers.
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Centralized Logging Service controller
(ClsController.exe) or agent
(ClsAgent.exe)commands and log collection
Frontend Hardware Load Balancer Ports if Using Only Hardware Load Balancing (HLB)
Following table is taken from : Ports and Protocols for Internal Servers > Hardware Load Balancer Ports if Using
Only Hardware Load Balancing
Load Balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Port
5061
444
135
80
8080
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
Front End Server load balancer
443
4443
5072
5073
5075
5076
5071
5080
Protocol
TCP (TLS)
HTTPS
DCOM and remote procedure call (RPC)
HTTP
TCP - Client and device retrieval of root certificate from
Front End Server – clients and devices authenticated by
NTLM
HTTPS
HTTPS (from reverse proxy)
TCP
TCP
TCP
TCP
TCP
TCP
Front End Server load balancer
Mediation Server load balancer
Front End Server load balancer (if the
pool also runs Mediation Server)
Director load balancer
Director load balancer
Director load balancer
Director load balancer
448
5070
5070
TCP
TCP
TCP
443
444
5061
4443
HTTPS
HTTPS
TCP
HTTPS (from reverse proxy)
Frontend Hardware Load Balancer Ports if Using DNS Load Balancing (DNS+HLB)
The following table is taken from Ports and Protocols for Internal Servers > Hardware Load Balancer Ports if Using
DNS Load Balancing
Load Balancer
Front End Server load
balancer
Front End Server load
balancer
Front End Server load
balancer
Front End Server load
balancer
Director load
balancer
Director load
balancer
Director load
balancer
Port
80
HTTP
Protocol
443
HTTPS
8080
4443
TCP - Client and device retrieval of root certificate from Front End Server –
clients and devices authenticated by NTLM
HTTPS (from reverse proxy)
443
HTTPS
444
HTTPS
4443
HTTPS (from reverse proxy)
Source References



Port Summary - Scaled Consolidated Edge with Hardware Load Balancers
Port Summary - Single Director
Ports and Protocols for Internal Servers