diff --git a/LDP/howto/docbook/NetMeeting-HOWTO.sgml b/LDP/howto/docbook/NetMeeting-HOWTO.sgml new file mode 100644 index 00000000..ae393545 --- /dev/null +++ b/LDP/howto/docbook/NetMeeting-HOWTO.sgml @@ -0,0 +1,1297 @@ + + +
+ + + + + Linux NETMEETING HOWTO + + Brent + Baccala + +
+ baccala@freesoft.org +
+ + + + Martin + Schiffers + +
+ mschiffers@axsi.net +
+ + + + + Mark + F. + Komarinski + Conversion from HTML to DocBook 3.1 + + + + + v1.0 + 13 January 2001 + bwb + + Initial public release + + + + v0.11 + 25 October 2000 + mfk + + Conversion to DocBook + + + + + + + This document aims to describe how to make Microsoft NetMeeting + interoperate with Linux. + + + + +
+ Introduction + + This is the Linux NETMEETING HOWTO; it describes + how to configure Linux for interoperation with Microsoft NetMeeting. + The latest copy of this document is available at + http://www.freesoft.org/software/NetMeeting + or from the + Linux Documentation Project + + + NetMeeting is Microsoft's client implementation of the H.323 + international standard teleconferencing protocol suite, providing + audio and video conferencing over an IP network. + NetMeeting also implements + the T.120 protocol suite, providing shared whiteboard, file + transfer and application sharing. As an extension, LDAP is + used for directory service. NetMeeting is included in Windows 2000 + and is freely available for download from + http://www.microsoft.com/windows/netmeeting + for Windows 95, 98, and NT. + + + Linux software is presently (October 2000) available to support H.323 + (both audio and video) and LDAP directory service, but not T.120 shared + whiteboard, file transfer, or application sharing. + + + If you don't know anything about H.323, I recommend these links: + + + + + http://www.openh323.org/ + + + + + http://www.databeam.com/h323/h323primer.html + + + + + http://www.hut.fi/~tttoivan/index4.html + + + + + ftp://ftp.intel.com/pub/H.323/DOCS + + + + + http://support.intel.com/support/videophone/trial21/H323_WPR.HTM + + + + + If you don't know anything about LDAP, I recommend these links: + + + + + http://www.openldap.org/ + + + + + http://www.umich.edu/~dirsvcs/ldap/index.html + + + + + RFCs 2251-2256 + + + + + If you have other links to recommend, or other suggestions for + improving this document, please email me at + baccala@freesoft.org + +
+
+ OpenH323 + +
+ What is it? + + OpenH323 is an open source implementation of the H.323 protocol suite. + As such, it can directly interoperate with Microsoft NetMeeting. At + the time of this writing (October 2000), OpenH323 is still early + in its development cycle; buggy and in flux, but useful. + + + OpenH323 consists of several C++ libraries and some C++ + client programs. + + + The most useful client programs are: + + + + List of client applications + + + + + ohphone + + H.323 interactive client. Linux equivalent to NetMeeting. + Supports audio and video; + no shared whiteboard, file transfer, or shared applications + + + + openam + + H.323 answering machine. Plays back a recorded message + and records incoming audio. No video support at present. + + + + forwarder + + Forwards H.323 sessions from one IP address/port to + another. Used to serve multiple H.323 destinations + from a single IP address. + + + + openmcu + + Multipoint Control Unit. Connects multiple sessions together + into a conference call. + + + + PSTN Gateway + + Allows NetMeeting clients to make phone calls onto the + conventional phone system - the Public Switched Telephone + Network (PSTN). Requires special hardware. + + + + +
+ + OpenH323 presently (October 2000) supports audio codecs G.711, G.723.1, + LPC-10, and GSM 06.10, as well as video codec H.261. + +
+
+ Why is it needed? + + OpenH323 is needed only if you want to make audio/video connections + with NetMeeting clients directly from your Linux system. It is not + needed to provide LDAP directory service to NetMeeting clients. + +
+
+ Where to get it? + + The main site is http://www.openh323.org/ + and contains links to a download page, mirror sites, mailing lists, + and other resources. + + + OhPhone, OpenAM, and PSTNgw are available as part of the standard + distribution, in both source and executable formats. + forwarder and openmcu are presently (December 2000) only available + from the CVS archive, as modules named "forwarder" and "openmcu". + +
+
+ Installation + + For OhPhone, OpenAM, and PSTNgw, download the executables. + If you want to build from source, perhaps because you need + forwarder or openmcu, you'll need the source code to the programs, + as well as to the pwlib and openh323 libraries. Compilation + instructions are available on the openh323 website. + +
+
+ Gatekeepers + + OpenH323 doesn't provide any gatekeepers itself, but several are + under construction based on its libraries. As of the end of 2000, + most of them are actively under development and quite primitive. + I haven't used any of them myself, but you want may to examine the + following links: + + + + + OpenGatekeeper + + + + + OpenH323 Gatekeeper + + + + + OpenGatekeeper H323 Proxy + + + +
+
+
+ NetMeeting directory kit + +
+ What is it? + + Each NetMeeting client can register with an LDAP server and + has a directory window that lists other + NetMeeting clients registered with the same server. + The NetMeeting directory kit is an extension to the OpenLDAP server + that provides directory service to NetMeeting clients. + +
+
+ Why is it needed? + + While NetMeeting can connect directly to another H.323 device by + specifying an IP address or DNS name, normally you'll want to use + an LDAP directory server. Using an LDAP server lets users see + a directory listing of available destinations, and is required + if you need to resolve aliases, for example if you want to serve + multiple H.323 destinations from a single IP address. A directory + server isn't required to connect directly from Linux + to a NetMeeting client; use OpenH323 for this. + + + The NetMeeting client violates the LDAP protocol in several ways, + so you'll have problems if you try using a standard LDAP server. + The NetMeeting directory kit corrects for these problems and allows + an OpenLDAP server to be used for NetMeeting directory service. + +
+
+ How it works + + Block diagram of NetMeeting directory kit + +___________________ _______ __________________ ______________ +| LDAP server | request | | | LDAP server | request| | +| | <-------| Perl |<--| | <------| NetMeeting | +| on private port | |script| | on public port | | client | +| (i.e, 2345) |-------> | |-->| 389 |------->| | +| | reply -------- | | reply -------------- +| | | | +------------------- ------------------ + + + The directory server consists of a 'master' LDAP server to + receive requests, a Perl script to correctly interpret + the Microsoft NetMeeting requests and, after interrogation + of a 'hidden' LDAP server, formats the results in a way that the + NetMeeting client can understand. + OpenLDAP's 'shell backend' is used to call the Perl script. + A custom schema is also required. + The script presently handles all of the above problems, with the + exception of timing out entries, which it doesn't do. + +
+ +
+ Where to get the software + + First of all you need to get the OpenLDAP software. + + + + Pre-built OpenLDAP software (i.e, RPMs) won't work unless + configured with support for the shell backend. + + + + You can download OpenLDAP from the main site located at + ftp://ftp.OpenLDAP.org/pub/OpenLDAP/openldap-release/ + or any mirror. + + + The NetMeeting directory kit is available from + http://www.freesoft.org/software/NetMeeting/download. + + + You need Perl 5, available from + http://www.perl.org, + but already included in all common Linux distributions. + You will also need the Net::LDAP module from the Perl CPAN archive, + which can be downloaded and installed directly from Perl: + + +[root@y2k baccala]# perl -MCPAN -e shell + +cpan shell -- CPAN exploration and modules installation (v1.58) +ReadLine support enabled + +cpan> install Net::LDAP + +... much output omitted ... + + /usr/bin/make install -- OK + +cpan> + + + If you've never used CPAN before, you will be prompted first with + a series of configuration questions. Once CPAN is configured, + the Net::LDAP module will be downloaded, compiled, and installed + automatically. + +
+
+ Installation + + Building OpenLDAP will require approximately 60 MB of free disk + space. Untar open-ldap-2.0.x.tgz + and configure it. + + + + Be sure to specify the shell backend function "--enable-shell" + + + +bash$ ./configure --enable-shell + + + Now build and install it with: + + +bash$ make + +... much output omitted ... + +bash# make install + + + It will normally install under /usr/local: + + + + Directories used by OpenLDAP + + + + + + /usr/local/lib + + + Shared and static libraries + + + + + /usr/local/bin + + + Client binaries for adding, deleting, + and searching LDAP servers + + + + + /usr/local/sbin + + + Utility programs for manipulating the raw database files. + Not needed for normal operation. + + + + + /usr/local/libexec + + + Various server programs, + including the slapd binary + + + + + /usr/local/etc/openldap + + + Contains the default configuration files + + + + + /usr/local/etc/openldap/schema + + + The different schemas used by the LDAP servers. + + + + + /usr/local/var/... + + + The location of the LDAP databases (in subdirectories) + + + + + /usr/local/man/... + + + Documentation + + + + +
+ + Once OpenLDAP has been installed, next install the NetMeeting + directory kit. + Untar ndk.tgz. + It contains these files: + + + + NetMeeting directory kit files + + + + + netmeeting.perl + + Perl script used to correct NetMeeting protocol violations + + + + netmeeting.schema + + Custom NetMeeting schema used by the LDAP server + + + + slapd.conf + + Sample config file for the master LDAP server + + + + slapd2.conf + + Sample config file for the slave LDAP server + + + + initialize + + Shell script used once to initialize the slave LDAP database + + + + slapd.rc + + /etc/rc.d/ script + + + + nmaddentry + + Perl script to add entries to the NetMeeting directory + + + + nmdirectory + + Perl/Tk script to query the NetMeeting directory + + + + +
+ + Copy netmeeting.perl to the + /usr/local/libexec directory, + netmeeting.schema to the + /usr/local/etc/openldap/schema + directory, + and copy both slapd.conf + and slapd2.conf to the + /usr/local/etc/openldap directory. + Create the directory + /usr/local/var/openldap-netmeeting + to store the LDAP database, and make it world writable. + + + Especially if you've changed the directories, edit + slapd.conf and slapd2.conf + and verify their configuration settings. + + + You will need to run two copies of slapd. + One uses slapd.conf + and must be started as root, since it binds to port 389. + The option can be specified to cause + slapd to chown + to an unprivileged user after binding the port (a wise precaution). + The other slapd + uses slapd2.conf, binds to an unprivileged + port, and only needs + sufficient privilege to write the database directory. + + +bash# /usr/local/libexec/slapd -f /usr/local/etc/openldap/slapd.conf -u nobody +bash$ /usr/local/libexec/slapd -h ldap://localhost:2345/ -f /usr/local/etc/openldap/slapd2.conf + + + You now have to initialize the slave database with a single entry. + This is only done once, by running the initialize + script + included in the kit. The "rootdn" and "rootpw" entries are + in the slave config file to allow access for the initialization + script, and must match the and + options in the script. + Once you've initialized the database with a single parent + entry, you can comment out the "rootdn" and "rootpw" lines + from slapd2.conf, though this is not critical. + + + The server should now be up and running. + For systems with /etc/rc.d/ + style initialization scripts (like RedHat), + the slapd.rc is provided to automate the + starting and stopping of the slapds. + +
+
+ Server Security + + As shown above, I run both slapds + as an unprivileged user, minimizing the possibility of compromised + security due to a bug in either the server software or the Perl + script. Of course, this requires the database directory + to be world writable so that the unprivileged slave server can + update it. This isn't as glaring a hole as it might first appear, + since the NetMeeting clients themselves use no authentication. + Thus, even if the database directory were better protected, + anyone on a local or remote host could use LDAP client + programs to delete or modify any of the database entries. + +
+
+ DNS issues with Windows 2000 + + Windows 2000 implements a modified DNS SRV + (RFC 2782), + an enhanced means of locating network servers, including LDAP. + To avoid delays in connecting to an LDAP server from a + Windows 2000 client, SRV records should be provided by the + DNS server. + ISC Bind + has supported SRV records since version 8.2.2. + As described in the + Bind + FAQ, the "check-names ignore" option is required to permit + underscores in the DNS names. Basically, if your NetMeeting server + name is "ils.freesoft.org", Microsoft Active Directory will expect + to use a subzone called "_msdcs.ils.freesoft.org". Within this + subzone, the "global catalog" server will be called + "gc._msdcs.ils.freesoft.org" and its LDAP SRV record will be called + "_ldap._tcp.gc._msdcs.ils.freesoft.org", as + described + by Microsoft. Got it? Your DNS database + entry will then look something like this: + + +$ORIGIN _msdcs.ils.freesoft.org. + +_ldap._tcp.gc IN SRV 1 1 389 ils.freesoft.org. + + + I've not yet been able to test this myself, not having a Windows 2000 + system, so any feedback would be appreciated. + +
+
+ Interoperation with other LDAP service + + The instructions above assume that your LDAP server is only + being used for NetMeeting directory service. Yet what if you + want to use a single server for both NetMeeting directory service + and other LDAP service? Only one server can be bound to port 389, + but OpenLDAP allows multiple database sections to be specified + in its configuration file, each serving different parts of the + LDAP namespace. NetMeeting uses only the "objectClass=RTPerson" + subtree, so as long as you avoid this subtree, you can configure + additional database sections to serve other subtrees with other + databases. The biggest problem you are likely to encounter is + the custom NetMeeting schema, which conflicts slightly with the + standard schema. Since the NetMeeting schema is more liberal + than the standard schema, I'd suggest commenting out the conflicting + parts of the standard schema. NetMeeting clients won't work with + the standard schema. See the LDAP RFCs and the OpenLDAP documentation + for more information about configuring LDAP servers. + +
+
+ +
+ Using the Software + +
+ Direct Connection + + You can use OpenH323's ohphone + program to connect directly to a + NetMeeting client. Specify the + option to indicate that you're + not using a gatekeeper, and either the DNS name or IP address of + the NetMeeting client: + + +bash$ ohphone -n 208.130.48.22 + + + + You can also start ohphone to receive incoming + calls from NetMeeting clients: + + +bash$ ohphone -n + + + + See the ohphone documentation for more information + on its additional features, including video conferencing, codec + selection, and auto-answer. + +
+ +
+ Directory Operation + + + Make sure you have an LDAP server running the NetMeeting directory kit, + as described above. + + + On the NetMeeting client, select the + + + Tools + + + Options + + + menu item to display a configuration dialog. Under the + "General" (NetMeeting 3) or "Calling" (NetMeeting 2) tab, + there will be a section for "Directory Settings". + Here you can enter the IP address or DNS name of the server. + The client will then attach to the server and register itself + either automatically, if the "Log on to directory server when + NetMeeting starts" checkbox is selected. + You can also log on to the directory server manually, by selecting + + + Call + + + Log on + + + . + + + If the user selects + + + Call + + + Directory + + , + a directory window will be displayed showing all users + registered on the LDAP server. + Double-clicking on one of the names will initiate a connection + to that user. + + + Querying the NetMeeting LDAP server from Linux can be done, but + is tricky because the client's IP address is stored in decimal, + and I don't mean dotted decimal. For example, the IP address + 63.216.69.197 is stored as 3309688895. Here's some + Perl code to convert back and forth from the NetMeeting + IP address format: + + +# Convert $addr (IP address or DNS name) to a NetMeeting decimal IP address + +use Socket; +$bytestring = inet_aton($addr); +if (defined $bytestring) { + ($sipaddress) = unpack('V', $bytestring); +} else { + die "Can't resolve $addr\n"; +} + +# Convert $sipaddress (from a NetMeeting LDAP server) into dotted decimal form + +$packedipaddr = pack 'V', $sipaddress; +$ipaddress = join '.', unpack('C4',$packedipaddr); + + + Included with the NetMeeting directory kit is + nmdirectory, a simple Perl/Tk script to query + a NetMeeting LDAP server and display the clients registered with it. + It's very primitive, and doesn't work well with large databases, + but provides a rudimentary example of how to interpret search + results from a NetMeeting LDAP server. + +
+ +
+ Linking From A Web Page + + + Microsoft Internet Explorer understands URLs with a "callto:" scheme + that specify NetMeeting destinations in one of two forms. When a + link with a "callto:" URL is selected, Internet Explorer runs + NetMeeting and directs it to connect to the specified destination. + + + The first URL form, "callto:destination", where 'destination' is + either an IP address or a DNS name, causes NetMeeting to open an + H.323 connection to port 1720 on 'destination'. Use this form + to connect directly to another NetMeeting or OpenH323 client. + + + The second URL form, "callto:server/alias", causes a directory lookup + on LDAP server 'server', searching for a CN attribute of 'alias'. + Assuming a match is found, a connection is made to the IP address + specified in the entry's sipAddress attribute. NetMeeting clients, + by default, register their user's E-mail addresses in the CN + attribute. Use this form to perform a directory lookup based + on E-mail address. + +
+ +
+ Permanent Directory Entries + + + NetMeeting clients aren't the only source of LDAP directory entries. + In particular, permanent directory entries can be manually inserted + into the LDAP server using the OpenLDAP client tools. Assuming the + attributes are specified properly, these entries will then appear in + NetMeeting directory listings and can be used as targets in "callto:" + URLs. This is useful when working with OpenH323 clients that don't + register themselves by default with the LDAP server. + + + To simply creating directory entries, the nmaddentry + script is included in the NetMeeting directory kit. Run it + without arguments for a usage message. For example, if you've + started ohphone on "y2k.freesoft.org", you + can register it with the LDAP server on "ils.freesoft.org" using + alias "baccala@freesoft.org" like this: + + +bash$ nmaddentry -h ils.freesoft.org baccala@freesoft.org y2k.freesoft.org +Successfully added cn=baccala@freesoft.org, objectclass=rtperson +bash$ + + + This entry will now appear in NetMeeting directory listings and + can be addressed as "ils.freesoft.org/baccala@freesoft.org". + The entry will automatically timeout after 30 minutes. + The switch creates a permanent directory + listing that won't time out, but this only works on + OpenLDAP servers using the NetMeeting directory kit. + To remove a permanent entry, + use the ldapdelete program + included with the OpenLDAP distribution, specifying the LDAP + Distinguished Name returned by nmaddentry: + + +bash$ ldapdelete -h ils.freesoft.org 'cn=baccala@freesoft.org,objectclass=rtperson' +bash$ + +
+ +
+ Serving Multiple Aliases + + The attributes registered by a NetMeeting client include 'sport', + the TCP port number it listens on for incoming H.323 requests, but + since this attribute is never retrieved in search requests, it + isn't as useful as it first appears. In fact, NetMeeting always + opens H.323 connections to the default port (1720), which raises + the question of how to serve multiple aliases from a single IP + address. + + + The key to doing this is the forwarder + program, included in the OpenH323 CVS archive. + forwarder listens for connections + on port 1720, and can be configured to redirect them based on the + alias being called. This allows calls for each alias to be sent to + a unique port number, where a program like ohphone + or openam is listening. + + + To use aliases, an LDAP directory is required, with an entry for each + alias. Each alias entry should specify a 'cn' attribute with the + alias name, and a 'sipAddress' attribute with the IP address of the + host where forwarder is listening. + + + I've successfully configured a single host to act as a combination + LDAP server (on port 389), forwarder + (on port 1720), and + ohphone and openam + clients on various private port numbers and remote systems. + +
+ +
+ Using the Answering Machine + + The OpenH323 answering machine, openam, will + listen for incoming H.323 connections, play a pre-recorded + message, and then record any audio sent to it into a file. + It can optionally be configured to run another program at the + end of the call, to email the recorded audio, perhaps. + + + It's usefulness is currently (December 2000) + limited by the lack of a gatekeeper + program clever enough to redirect calls to it if there's no + answer at the main address. Thus, it will only act as an + answering machine if the ohphone program + is running at the main address, and has been configured to + redirect calls to another address, using + the + and options. + +
+ +
+ Conference Calls + + The openmcu program, in the OpenH323 CVS + archive, implements an H.323 Multipoint Control Unit (MCU). + Multiple NetMeeting or ohphone clients + can connect to the MCU and form a conference call. As of + December 2000, the quality and reliability of the connection + is problematic, but hopefully this will improve. + +
+ +
+ Routing Calls Through NAT + + + Special support is required on a NAT (IP Masquerade) + router to allow H.323 traffic to + pass through. If the NAT router is running Linux, a masquerading + module can be found at http://www.coritel.it/projects/sofia/nat.html. + + + + I have not actually tested this software. + + +
+ +
+ Custom Configurations + + + The server capabilities can be customized by modifying the + 'netmeeting.perl' script. For example, + calls for stale entries could be redirected to an + "forwarder" configured to hand off to "openam" answering + machines. Thus, calls to a unavailable user would be answered + and recorded for later playback. + + + As OpenH323's development continues, it's expected that + these techniques will become more sophisticated, for example + by ringing the user first and only forwarding to an answering + machine if there's no answer after a given time. + Such functionality would most likely be placed in a gatekeeper. + +
+
+ +
+ Debugging + + + For debugging the NetMeeting directory kit Brent Baccala suggests using + ethereal (http://ethereal.zing.org/) + to do a packet trace. It's LDAP support is quite good. There + is also a trace file option in the Perl script "netmeeting.perl" + that can be uncommented. + + + You might also try running the slapds with debugging turned on + (-d 768 is a good start), but their messages are rather confusing. + + + For debugging H.323, try using the "-t" and "-o" options, supported + by all the OpenH323 client programs. + + +
+ + + LDAP attributes used by NetMeeting + + Distinguished Names (DNs) used by NetMeeting must always + end in "objectclass=rtperson". + The following LDAP attributes are used by NetMeeting: + + + NetMeeting LDAP attributes + + + + objectClass + must be "RTPerson" + + + cn + alias used for directory lookups; must be present + + + sappid + must be "ms-netmeeting" + + + sprotid + must be "h323" + + + sprotmimetype + typically "text/h323"; unused + + + smimetype + typically "text/iuls"; unused + + + sflags + must be 1 + + + sappguid + unknown + + + smodop + unknown + + + sipaddress + decimal IP address + + + sport + TCP port number; unused + + + ssecurity + unknown + + + sttl + entry timeout value in minutes + + + c + two digit country code + + + rfc822mailbox + email address + + + givenname + optional + + + surname + optional + + + comment + optional + + + location + optional + + + ilsa39321630 + 1 = personal; 2 = business; 4 = adult + + + ilsa32833566 + 0 = not audio capable; 1 = audio capable + + + ilsa32964638 + 0 = not video capable; 1 = video capable + + + ilsa26214430 + 0 = not in a call; 1 = currently in a call + + + ilsa26279966 + unknown + + + +
+ + NetMeeting uses a non-standard means of refreshing dynamic entries. + The Microsoft server maintains an "sttl" attribute, which is a + time to live for the entry in minutes. A search request for + attribute "sttl" resets the timer. If the timer goes to zero, + the entry is supposed to disappear from the database. Of course, + the sttl attribute doesn't actually exist in the database, and + the client doesn't bother to give us the whole DN it wants updated, + only supplying the "cn" component in the search request. + + + + + NetMeeting LDAP protocol violations + + As mentioned, NetMeeting violates the LDAP protocol in several ways. + For the record, NetMeeting: + + + + + Doesn't structure Distinguished Names (DNs) properly + +
+ + NetMeeting puts the most significant elements in the DN first, + instead of last, using: + +
+
+ + C=US, O=Microsoft, CN=xxx@abc.com, OBJECTCLASS=rtperson + +
+
+ + instead of the proper formating, which is: + +
+
+ + CN=xxx@abc.com, O=Microsoft, C=US + +
+ + + + Doesn't include the required "objectclass" attribute + +
+ + Instead, it tacks an "OBJECTCLASS" element to the end of the DN, + as shown above. + +
+ + + + Doesn't insert parents into the LDAP server + +
+ + This is a clear violation of the LDAP standard, which requires + parents to exist before children can be created. I.e, to insert + this DN: + +
+
+ + CN=xxx@abc.com, O=Microsoft, C=US + +
+
+ + this DN must already exist: + +
+
+ + O=Microsoft, C=US + +
+
+ + as must this one: + +
+
+ + C=US + +
+ + + + Doesn't understand attribute aliases, and is therefore unable + to recognize that "sn" and "surname" refer to the same attribute. + + + + + Requires that attributes in a search request be returned in + exactly the same order they were requested, a requirement not + guaranteed by the OpenLDAP server. + + + + + Specifies "base" scope in search requests, when it really should + use "sub", since it wants a list of entries, not just one + + + + + Uses the "%" character as wildcard in search requests, instead + of the "*" character specified by the standard. + + + + + Uses a non-standard means of refreshing dynamic entries. + + + The Microsoft server maintains an "sttl" attribute, which is a + time to live for the entry in minutes. A search request for + attribute "sttl" resets the timer. If the timer goes to zero, + the entry is supposed to disappear from the database. + NetMeeting 2 supplies an "sttl" attribute, but + NetMeeting 3 doesn't actually + create the "sttl" attribute at all. Also, + the client doesn't bother to give us the whole DN it wants updated, + only supplying the "cn" component. + + + + + + + Interoperation with Cisco + + Both NetMeeting and OpenH323 can interoperate with Cisco's + voice capable routers. To successfully initiate calls from + a Cisco to an OpenH323 (i.e, Linux) client, the G.711 codec + must be explicitly specified. For example, with the following + configuration, dialing "911" on the Cisco will place a call + to a Linux system (10.1.1.1) running OpenH323: + + +dial-peer voice 911 voip + destination-pattern 911 + session target ipv4:10.1.1.1 + codec g711ulaw + + + To call from Linux to a Cisco, use ohphone + with a argument. + should be a phone number that's been configured on the Cisco + using a dial-peer statement. For example, + this will call number "111" on a Cisco (10.1.1.10): + + +bash$ ohphone -n 111@10.1.1.10 + + + To call from NetMeeting to a Cisco, select the Cisco as a gateway. + To do this from NetMeeting, select + + Tools + Options + . + For NetMeeting 2, select + + Audio + , check the box labeled "Use H.323 gateway", and + enter the Cisco's DNS or IP address. + For NetMeeting 3, select + + General + Advanced Calling... + , check the box labeled "Use a gateway..." + (not gatekeeper) and enter the Cisco's address. + Now, you can type a phone number directly into NetMeeting's address + panel and it will be relayed to the Cisco and resolved there, using + the Cisco's configured dialing rules. + If you're using NetMeeting 2, you'll need to select + "H.323 Gateway" from the "Call using:" list when you initiate the call. + + + + + Thanks + + Many thanks have to go to Brent Baccala, who wrote the + NetMeeting directory kit, also for his 24-hour E-mail tech support, and + encouragement. Without him I would have passed a many nights more to + set it up at my own. + + + +
+