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Snom 4S Administrator's Manual

Snom 4S Administrator's Manual

Sip proxy/registrar version 2.21
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Administrator's
Manual
snom 4S
SIP Proxy/Registrar
Version 2.21

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Summary of Contents for Snom 4S

  • Page 1 Administrator‘s Manual snom 4S SIP Proxy/Registrar Version 2.21...
  • Page 2 © 2002 snom technology Aktiengesellschaft. All Rights Reserved. This document is supplied by snom technology AG for information purposes only to licensed users of the snom 4S registrar proxy and is supplied on an “AS IS” basis, that is, without any warranties whatsoever, express or implied.

  • Page 3: Welcome To The Sip World

    That is why we are making this simple and straightforward proxy available. snom 4S stands for “snom soft switch for small and medium enterprises“. That means, the snom 4S proxy was designed for environments handling up to 1000 users with normal traffic.
  • Page 4 E G I S T R A R A N U A L to run the SIP proxy. For additional snom 4S information, please visit our Web site at http://www.snomag.de and if you have any comments and suggestions about snom 4S, please contact us through snom technology AG’s support link Web site.

  • Page 5: Table Of Contents

    Uninstalling in Windows ............. 23 Linux Installation ..............24 General Concepts .............27 Security ................. 27 Reliabilty ................. 28 State ..................29 Overlap Dialling ................ 30 Sequential Forking ..............30 Network Address Translation ............31 Routing ................... 32 snom technology AG • 5...
  • Page 6 Dial Plan.................. 45 Error-Information ..............49 Welcome Message..............52 DNS..................53 Server Farm Operation .............. 54 Registering Phones ..........57 snom 100 Registration............... 57 Microsoft Messenger Registration ..........58 Maintenance.............61 Registered Users ..............61 Call Logs ................. 62 SIP Message Flow ..............65 Logging ...................

  • Page 7: The Voice Over Internet Protocol

    In the mid 90s, H.323 was the first attempt to unify the VoIP industry under a common standard,and move the world of telephony into the computer industry, using most of the methods known from ISDN. Seen however, from today’s perspective, the resulting technology was snom technology AG • 7...

  • Page 8: Open Standards

    4 S P S N O M R O X Y E G I S T R A R A N U A L far too complex, so products based on this technology did not work well together. The late introduction of “supplementary services” (H.450.x) not only introduced another level of complexity, but was also simply too late.

  • Page 9: What You Can Expect And What Not

    It is important that users know what to expect: Cell phone users know that driving through a tunnel may break the call, and Internet telephony users must be aware that talking for free may compromise call quality. snom technology AG • 9...
  • Page 10 4 S P S N O M R O X Y E G I S T R A R A N U A L 10 • About VoIP...

  • Page 11: The Sip Architecture

    (somebody being the user agent client, UAC and somebody the user agent server, UAS). In SIP, there is no conceptual difference between a hard phone and a soft phone. The snom 100 VoIP phone or Microsoft Messenger are examples of this kind of system.

  • Page 12: Proxies

    When the responses come back from the destinations, the proxy merges the responses, determines the best result and passes it down to the user agent that sent the request (UAC). The snom 4S proxy is a stateful proxy. Location Server From RFC3261 we read: „A location service is used by a SIP...

  • Page 13: Media Server

    The conference server also checks the credentials of participants joining the conference. The snom 4s is an example of this technology. Gateways From a SIP perspective, the gateway is also just a user agent.
  • Page 14 R O X Y E G I S T R A R A N U A L Mediatrix, Sonus and Vegastream. The snom 4s gateway is a SIP NAT gateway software enabling Linux computers to be SIP-aware. 14 • SIP Architecture...

  • Page 15: Snom 4S Framework

    Linux computers. The registar proxy is the core part of this framework. Proxy The snom 4S registrar proxy is a SIP registrar and proxy with the following features: • Stateful forking. Requests are forked to one or more destinations and the responses are filtered before passing them back to the user agent client.

  • Page 16: Sip Nat Gateway

    SIP NAT Gateway The snom 4S Network Address Translation (NAT) gateway is a stateless proxy that transports SIP messages between private and public networks. This makes it possible to share one public Internet address amongst several SIP elements.

  • Page 17: Media Server

    • Error explanations. When something goes wrong, the media server explains what it was . snom technology AG • 17...
  • Page 18 4 S P S N O M R O X Y E G I S T R A R A N U A L 18 • snom 4S Framework...

  • Page 19: Installation

    Important: If you are doing an update, you need to stop and uninstall the old proxy first (see below). After double clicking on the setup executable, the installations program starts up (see fig. x-1). Press Next to begin the installation. Figure 4-1: Installation Welcome Screen snom technology AG • 19...
  • Page 20 4 S P S N O M R O X Y E G I S T R A R A N U A L At the beginning of the installation the setup program asks you to accept the license conditions (see fig. x-2). Please read them carefully, then select the “accept”...
  • Page 21 The default port for web servers is 80, and if you are not running any other web services on the computer, port 80 is a good choice. Otherwise, choose a free port and write the port number down somewhere Figure 4-3: Installation Customer Information snom technology AG • 21...
  • Page 22 Check that the installation has been successful by checking the Services field of Windows. Open the services Window and look for “snom 4S SIP Proxy/Registrar”. The status should be “Started”. If this is not the Figure 4-5: Software Dialog in Windows...

  • Page 23: Uninstalling In Windows

    Uninstalling in Windows To uninstall the proxy, first stop it in the services window. Then go to the Software Window and click on “remove” for snom 4S proxy Server. Figure 4-6: Services in Windows...

  • Page 24: Linux Installation

    4 S P S N O M R O X Y E G I S T R A R A N U A L Linux Installation Manual Starting If you just want to try the proxy, it should be enough to start the proxy manually.
  • Page 25 30 Aug 24 11:42 proxy -> snom_sip_proxy-i386-linux-2.12 -rw------- 1 root root 1472 Aug 22 16:17 proxy.txt lrwxrwxrwx 1 root root 57 Aug 24 11:42 proxy_manual.pdf -> snom_sip_proxy-i386-linux-2.12/snom 4S SIP Proxy-2.12.pdf drwxr-xr-x 2 root root 73728 Aug 24 11:56 registrations drwx--x--x 3 root root 4096 Aug 12 14:09 snom_sip_proxy-i386-linux-2.11...
  • Page 26 4 S P S N O M R O X Y E G I S T R A R A N U A L To update a version, copy the latest tarball into the directory and run the install script of the new version. It will automatically shut down the old proxy and run the new one.

  • Page 27: General Concepts

    • The proxy checks if the answer is correct and corresponds to an open question. If that is the case, the request passes; if not the proxy generates another question. snom technology AG • 27...

  • Page 28: Reliabilty

    4 S P S N O M R O X Y E G I S T R A R A N U A L The answer depends on the realm, the username and the password stored in the proxy and in the user agent. By looking at the answer, it is not possible to find out anything about the password or username.

  • Page 29: State

    To avoid this, the latest SIP standard recommends using a different transport layer for this, TCP. The snom 4S proxy supports both transport layers and automatically detects whether an old SIP device cannot handle TCP packets.

  • Page 30: Overlap Dialling

    When a telephone user dials a number, she or he does not have to press enter to start the call in a traditional telephone system. There are two ways to achieve this with the snom 4S: • Where the length of a telephone number can be determined by a simple rule, a dial plan is used.

  • Page 31: Network Address Translation

    IP addresses. Whenever a packet arrives at the NAT from the public Internet, the NAT gateway looks into the list and forwards the packet to the associated computer and port. When a packet arrives from a private snom technology AG • 31...

  • Page 32: Routing

    Unfortunately, the first proposals for doing this did this in a complicated way that can cause problems under certain circumstances. For this reason, “loose routing”, a new and better way of routing messages was developed. The snom 4S supports both routing methods. 32 • General Concepts...

  • Page 33: Configuration

    IP addresses of the proxy (if not proposed correctly) and the license key that you received with the software. If you don’t have a license key, contact mailto:support@snom.de for one. After saving this page, the license type and the number of currently registered users is displayed on top of the page.
  • Page 34 4 S P S N O M R O X Y E G I S T R A R A N U A L Hostnames You need to enter a list of names that the proxy feels responsible for. When a packet arrives at the proxy, the proxy checks the given hostname against the list you enter in this field.

  • Page 35: License Key

    If the web client shows „not licensed“, please send the list oh hostnames and the IP addresses to mailto:support@snom.de. General Settings There are a number of general settings that you should set up in the beginning.

  • Page 36: Sip Port

    If there is only proxy, the default value should be set to “snom”, but if packets might run over several proxies, you should choose a more unique value like “SIP proxy on...

  • Page 37: Tcp Threshold

    TCP threshold SIP uses both reliable and non-reliable transport layers. The snom proxy version 2.14 supports UDP and TCP transport layers. When the proxy needs to send a request, it has to make a decision which transport layer to use. The TCP threshold value is compared against the packet length.

  • Page 38: Registration

    4 S P S N O M R O X Y E G I S T R A R A N U A L only basic security, as the content of the web page is transmitted without encryption over the network and the passwords can easily monitored by network specialists.

  • Page 39: Save Registrations To File

    1.0. A good value is 0.5 or 1.0. Reject Registrations Across NAT When a user agent registers, it provides a contact and a path that tell the registrar how the user agent can be reached. If the packet goes snom technology AG • 39...

  • Page 40: Routing

    4 S P S N O M R O X Y E G I S T R A R A N U A L through NAT-aware equipment, the proxy will get not only the private address but also the qay to get there (see the Path header). When a user agent from a private address registers without a path at a public address, the registration will fail in most cases.

  • Page 41: Max Forwards

    (NAT) gateway or a firewall. The criterion for this is when the proxy is in a private network address space and the destination is a public address. The NAT gateway setting has the same format as the PSTN gateway setting. snom technology AG • 41...

  • Page 42: Do Not Signal Loose Routing

    4 S P S N O M R O X Y E G I S T R A R A N U A L Do not signal loose routing Although loose routing is mandatory for new SIP equipment and is compatible with the old routing method (“strict routing”), some equipment can still cause headaches.

  • Page 43: Domain Administration

    The default domain of the proxy is the domain list you entered during the licensing of the proxy. This list cannot be deleted and is the default when you don‘t enter a domain name in other parts of the proxy. snom technology AG • 43...

  • Page 44: User Administration

    4 S P S N O M R O X Y E G I S T R A R A N U A L User Administration The “well-known” users of the proxy may be challenged on registration and on forwarding requests. This way you can ensure that users are really who they claim to be, and give them special rights (e.g.

  • Page 45: Dial Plan

    Checking the user/group limits the pattern to a specific list of users. This way you could, for example, grant the sales people the right to make international calls, while everybody else is limited to local calls. snom technology AG • 45...
  • Page 46 4 S P S N O M R O X Y E G I S T R A R A N U A L Looking at the destination you can find out if the call is local, international, going to the boss, and so on. The matching process is done using the following “wildcards”: •...
  • Page 47 Rule 1 tells to use the PSTN gateway where at least four digits are available and the called proxy is the local proxy. The star behind the tilde matches port numbers which might be part of the URL. This can be left snom technology AG • 47...
  • Page 48 4 S P S N O M R O X Y E G I S T R A R A N U A L out when all attached SIP devices use the latest SIP draft for generating URLs. The destination will be the dialled number plus the string “@gw”, which would be the gateway in this installation.

  • Page 49: Error-Information

    This means that the system is much smarter than traditional telephone systems. You can even customize the announcements according to your special requirements. snom technology AG • 49...
  • Page 50 4 S P S N O M R O X Y E G I S T R A R A N U A L You can simply set up the error information redirection by selecting the approriate error type and enter the destination that should be put into the response.
  • Page 51 504 Server Time-out There was no response from a network element. 505 Version Not Supported There is a problem with the SIP version used. 513 Message Too Large The message is too large to be processed. snom technology AG • 51...

  • Page 52: Welcome Message

    4 S P S N O M R O X Y E G I S T R A R A N U A L 600 Busy Everywhere There is really a big problem and something for the system administrator. 603 Decline A network element refuses to work at this time.

  • Page 53: Dns

    A N U A L What is DNS? The domain name system (DNS) is a powerful mechanism to make internet addresses human-readable. “www.snom.de” is much easier to remember than 192.67.198.4. But there are also other reasons to use DNS: If the underlying address changes, the user does not have to change all the addresses in his or her address book.

  • Page 54: Server Farm Operation

    S N O M R O X Y E G I S T R A R A N U A L $TTL 1D anycom.de. IN SOA fox.anycom.de. hostmaster.snom.de. ( 2002050111 ; serial ; refresh ; retry ; expiry 1D ) ; minimum...
  • Page 55 It has to be noted here that the exchange of the necessary information between the proxies runs with a propretary extension of the SIP protocol. Because of this, the redundancy setup of the snom 4S SIP proxy will not work with proxies from other vendors. However, as the whole system can be viewed as a proxy, that should not be reason for concern.
  • Page 56 4 S P S N O M R O X Y E G I S T R A R A N U A L For making the exchange of registration information more secure, you can enter a username and a password. This will be used by the proxy for challenging incoming replication requests.

  • Page 57: Registering Phones

    Registering Phones As an example, we show you here how to register a snom 100 VoIP phone and a Microsoft Messenger with the proxy. Important: Before you can try this on your proxy, you need to set up the proxy.

  • Page 58: Microsoft Messenger Registration

    E G I S T R A R A N U A L Microsoft Messenger Registration Microsoft Messenger supports SIP from Version 4.6 ongoing. To register the messenger with a snom proxy, you need to carry out the following steps: • Open Microsoft Messenger •...
  • Page 59 E G I S T R A R A N U A L proxy. If you go to the trace page of the proxy, you can see the registration messages: Figure 7-2: Options for Microsoft Messenger snom technology AG • 59...
  • Page 60 A N U A L You then can make your first test call. The snom 4S Proxy/Registrar supports presence and instant messaging with the Microsoft Messenger. Just enter the contact that you would like to see; the proxy will handle the traffic to the registered Microsoft Messenger client.

  • Page 61: Maintenance

    The path is optional. • User-Agent: The user agent identification tells the proxy if a license is required. • Probability: The probability of the registration. Users are searched according to their probability. snom technology AG • 61...

  • Page 62: Call Logs

    4 S P S N O M R O X Y E G I S T R A R A N U A L • Expires: The expiry time in seconds. If you click on the link behind this number, you get to the SIP message trace that is associated with the registration.

  • Page 63: Call Logs In The Web Interface

    The call log stores only the last 100 calls and discards older calls. The call log is only reliable in so far as the involved network elements follow the loose routing of the proxy. If network elements violate this rule, snom technology AG • 63...

  • Page 64: Pending Calls

    4 S P S N O M R O X Y E G I S T R A R A N U A L the packets do not flow through the proxy and the proxy is not able to determine the length of the call. Please remember that the call log is sensitive information and should not be accessible to unauthorized persons.

  • Page 65: Sip Message Flow

    Here you can see which transport layer (UDP or TCP) was used, the IP address of the source or destination, and the port that was involved. • Header: Here you can see the first line of the SIP message. snom technology AG • 65...
  • Page 66 4 S P S N O M R O X Y E G I S T R A R A N U A L By clicking on the header line, you get the whole packet: The proxy actually keeps more messages than are displayed on this list.

  • Page 67: Logging

    However, the packets are kept in the call flow analysis log and on the registration page. Logging If you want to see the log file, just go to the Log file menu item. To clear the log, go to the bottom and click on “Clear”. snom technology AG • 67...
  • Page 68 4 S P S N O M R O X Y E G I S T R A R A N U A L 68 • Maintenance...

  • Page 69: More Information

    Standards The standards used for this proxy are open in the sense than not only snom is using them. Feel free to take a look at the underlying standards. General web page for standards: http://www.ietf.org/internet-drafts SIP working group drafts: http://www.softarmor.com/sipwg/drafts and...

  • Page 70: Other Useful Information

    Other useful information General Information: http://iptel.org Windows Messenger: http://www.microsoft.com/WindowsXP/pro/techinfo/ planning/networking/windowsmessenger.asp snom home page: http://www.snom.de Footnotes This standard is now obsolete. Many products currently on the market are compatible with this obsolete RFC. You should be aware of this when buying SIP technology.

  • Page 71: Index

    Installation 19 Delete 60 Installation Directory 20 DHCP 11 Instant Messaging 11 Dial Plan 45 Interoperability 3, 8, 16 Dial plan 15 IPchains 16 DiffSrv 7 ISDN 7 DNS 11, 52 DNS SRV 28 DSL 16 snom technology AG • 71...
  • Page 72 Path registration 15, 16 SIP Message Flow 63 Ports 21 SIP NAT Gateway 16 PPPoE 16 SNMP 11 Private IP Address 31 snom 100 Registration 55 Private Networks 16 Soft Switch 3 Probability 9, 30, 59 State 29 Proxies 12 Stateful Forking 15...
  • Page 73 Supplementary Services 8 Switched Network 7 TCP threshold 39 Transfer 9 Transport Layer 16, 29 UAC 32 UAS 32 Uninstalling 23 User 59 User-Agent 11, 59 VLAN 7 VoIP 7 Web Access 16 Wildcards 46 snom technology AG • 73...
  • Page 74 USA Representation Pascalstr. 10E, 10587 Berlin, Germany ABP International, Inc. Phone: +49 (30) 39833-0 Crestside Dr. mailto: info@snom.de Coppell, Texas 75019, USA http: www.snom.de Phone: +1-972-831-0280 sip: info@snomag.de sip: usa@snomag.de mailto: usa@snom.de © 2002 snom technology AG All rights reserved.

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