Dear All Please be informed that I checked for the presence of internal modem on my CentOS server , as the followings : #dmesg |grep -i modem #lspci |grep -i modem #lshw |grep -i modem According to the output , it seems that my CentOS client does not contain internal modem . So I decided to add external USB modem and make use of an PCAnyWhere like application that enables for Remote PC Access . Can you please do me favor and let me know how can I add the external USB modem to my CentOS host and please propose for an PCAnyWhere like application that can be installed on my CentOS client and enables for remote dialup connection (as the PCAnyWhere does for the MS Windows clients) ? Let me thank you in advance Regards H.Motamedi
hadi motamedi wrote:
Dear All Please be informed that I checked for the presence of internal modem on my CentOS server , as the followings : #dmesg |grep -i modem #lspci |grep -i modem #lshw |grep -i modem According to the output , it seems that my CentOS client does not contain internal modem . So I decided to add external USB modem and make use of an PCAnyWhere like application that enables for Remote PC Access . Can you please do me favor and let me know how can I add the external USB modem to my CentOS host and please propose for an PCAnyWhere like application that can be installed on my CentOS client and enables for remote dialup connection (as the PCAnyWhere does for the MS Windows clients) ?
I would use a serial modem, assuming your server has a serial port... and then configure a tty on that serial port, along with the modem autoanswer.
CentOS has mgetty, so in /etc/inittab, you add a line like...
S3:345:respawn:/sbin/mgetty -x3 ttyS0 (for com1 which is dev/tty0)
and configure your modem options in /etc/mgetty+sendfax/mgetty.config
now, you can use a dialup terminal program such as minicom, hyperterm, etc and dial into that modem on the CentOS system, and get a serial login prompt.
sadly, I haven't set this sort of thing up in so many years, Ive forgotten all the specifics. these days, we just use ssh over the internet
Thank you very much for your help . Can you please do me favor and confirm if the scenario works when both ends are as CentOS (I mean my CentOS server at the office connected to the telephone line and the remote CentOS client at the far site that we need to have remote access to it) ? Thank you in advance
On Mon, Oct 26, 2009 at 5:42 AM, John R Pierce pierce@hogranch.com wrote:
hadi motamedi wrote:
Dear All Please be informed that I checked for the presence of internal modem on my CentOS server , as the followings : #dmesg |grep -i modem #lspci |grep -i modem #lshw |grep -i modem According to the output , it seems that my CentOS client does not contain internal modem . So I decided to add external USB modem and make use of an PCAnyWhere like application that enables for Remote PC Access . Can you please do me favor and let me know how can I add the external USB modem to my CentOS host and please propose for an PCAnyWhere like application that can be installed on my CentOS client and enables for remote dialup connection (as the PCAnyWhere does for the MS Windows clients) ?
I would use a serial modem, assuming your server has a serial port... and then configure a tty on that serial port, along with the modem autoanswer.
CentOS has mgetty, so in /etc/inittab, you add a line like...
S3:345:respawn:/sbin/mgetty -x3 ttyS0 (for com1 which is dev/tty0)
and configure your modem options in /etc/mgetty+sendfax/mgetty.config
now, you can use a dialup terminal program such as minicom, hyperterm, etc and dial into that modem on the CentOS system, and get a serial login prompt.
sadly, I haven't set this sort of thing up in so many years, Ive forgotten all the specifics. these days, we just use ssh over the internet
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
hadi motamedi wrote:
Thank you very much for your help . Can you please do me favor and confirm if the scenario works when both ends are as CentOS (I mean my CentOS server at the office connected to the telephone line and the remote CentOS client at the far site that we need to have remote access to it) ? Thank you in advance
Running mgetty on the answering side will work with Centos running some dial-out terminal application like kermit, minicom, or cu. But what you'll get is a separate command line login, not a GUI desktop or copy of what is on the console. If you want more than that, you might set up dial-in PPP so you can treat the connection as a network address with all the usual tools. I'm not sure if this is exactly right for Centos but it should be close: http://www.howtoforge.com/linux_dialin_server. Mgetty should be able to detect if you are using dial-up networking from the other end and permit connection either way.
Thank you very much for your reply . According to your message , the minicom is not suitable in this regard as I really want remote desktop access to my CentOS client located at far site and thus get its keyboard & mouse control to issue commands and view Gui . Please do me favor and propose for the solutions that can enable my CentOS server at the office to get remote desktop access of my CentOS client far at the site (the only connections that can be made is through modem dialup connections) . Let me thank you in advance
On Mon, Oct 26, 2009 at 12:40 PM, Les Mikesell lesmikesell@gmail.comwrote:
hadi motamedi wrote:
Thank you very much for your help . Can you please do me favor and confirm if the scenario works when both ends are as CentOS (I mean my CentOS server at the office connected to the telephone line and the remote CentOS client at the far site that we need to have remote access to it) ? Thank you in advance
Running mgetty on the answering side will work with Centos running some dial-out terminal application like kermit, minicom, or cu. But what you'll get is a separate command line login, not a GUI desktop or copy of what is on the console. If you want more than that, you might set up dial-in PPP so you can treat the connection as a network address with all the usual tools. I'm not sure if this is exactly right for Centos but it should be close: http://www.howtoforge.com/linux_dialin_server. Mgetty should be able to detect if you are using dial-up networking from the other end and permit connection either way.
-- Les Mikesell lesmikesell@gmail.com
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
hadi motamedi wrote:
Thank you very much for your reply . According to your message , the minicom is not suitable in this regard as I really want remote desktop access to my CentOS client located at far site and thus get its keyboard & mouse control to issue commands and view Gui . Please do me favor and propose for the solutions that can enable my CentOS server at the office to get remote desktop access of my CentOS client far at the site (the only connections that can be made is through modem dialup connections) .
GUI over a 28k dialup? ouch. there's no network connection at this remote site? its going to be really really slow over dialup. I'm talking minutes to paint a screen at 2-3kbyte/sec serial speeds (a 1280x1024 24bit desktop is 3.6 million bytes). use a really simple theme on the desktop with no shaded borders, no backgroun graphics ('wallpaper'), etc. Sending a single full screen 1280x1024 photographic image could take a half hour or more.
FreeNX is probably your best bet. i've never set it up, so you'll need to find someone elses HOWTO ... NX protocol runs over TCP/IP networking, so you'll be setting up your modem (I still recommend a serial modem) to answer a PPP dialinn TCP session, which you'll connect to with a PPP dialup session much as we did for the internet in the days before broadband.
linux can be completely managed via shell. NONE of the dozens of unix servers I manage have any sort of console screen attached to them.
John R Pierce wrote, On 10/27/2009 02:42 AM:
GUI over a 28k dialup? ouch. there's no network connection at this remote site? its going to be really really slow over dialup. I'm talking minutes to paint a screen at 2-3kbyte/sec serial speeds (a 1280x1024 24bit desktop is 3.6 million bytes). use a really simple theme on the desktop with no shaded borders, no backgroun graphics ('wallpaper'), etc. Sending a single full screen 1280x1024 photographic image could take a half hour or more.
You Kids and your full desktop hosted back... back in the day I worked with individual applications across a 9.6kbps connection, and yes it was slow and had a bit of lag, but it worked well enough to use xemacs and mozilla across. Also when hosting the application back, you are not transferring all the pixels, but only the X commands to draw them, so unless you are running a picture editor/viewer (such as gimp) then a lot less than your 3.6 million bytes per 1280X1024x24bit will be used. Granted, running the gimp full screen across such a link would be a near insane thing.
I was much happier when I discovered `ssh -C` (in combination with X or Y), to host the apps back. There was still a little lag but overall it was _much_ snappier.
I have yet to use X across a vnc or with freenx so I can't comment on how they compare to `ssh -C`.
John R Pierce wrote, On 10/27/2009 02:42 AM:
GUI over a 28k dialup? ouch. there's no network connection at this remote site? its going to be really really slow over dialup. I'm talking minutes to paint a screen at 2-3kbyte/sec serial speeds (a 1280x1024 24bit desktop is 3.6 million bytes). use a really simple theme on the desktop with no shaded borders, no backgroun graphics ('wallpaper'), etc. Sending a single full screen 1280x1024 photographic image could take a half hour or more.
You Kids and your full desktop hosted back... back in the day I worked with individual applications across a 9.6kbps connection, and yes it was slow and had a bit of lag, but it worked well enough to use xemacs and mozilla across. Also when
<snip> Man, talk about a time traveller! How'd you get a copy of firefox back to when we only had Netscape?
mark "and that was 14.4k"
On Tue, 27 Oct 2009, John R Pierce wrote:
Netscape? Try NCSA Mosaic... Where I lived, the best my modem would do most of the time 19-21kbps... Gopher and/or UUCP was more useful.
We regularly test web apps with lynx, elinks and w3m -- I opened a ticket on that just yesterday with one of my developers, and seek w3m conformance
As a result, usability on cell phone (pda, etc) browsers, which are somewhat sketchy, is also good
-- Russ herrold
m.roth@5-cent.us wrote:
Man, talk about a time traveller! How'd you get a copy of firefox back to when we only had Netscape?
Netscape? Try NCSA Mosaic... Where I lived, the best my modem would do most of the time 19-21kbps... Gopher and/or UUCP was more useful.
That far back... hell, usenet for me, and I still use it. Kids these days,everything's gotta have a gui, 'cause they can't read, and learn COMMANDS?!
mark
m.roth@5-cent.us wrote, On 10/27/2009 12:31 PM:
John R Pierce wrote, On 10/27/2009 02:42 AM:
GUI over a 28k dialup? ouch. there's no network connection at this remote site? its going to be really really slow over dialup. I'm talking minutes to paint a screen at 2-3kbyte/sec serial speeds (a 1280x1024 24bit desktop is 3.6 million bytes). use a really simple theme on the desktop with no shaded borders, no backgroun graphics ('wallpaper'), etc. Sending a single full screen 1280x1024 photographic image could take a half hour or more.
You Kids and your full desktop hosted back... back in the day I worked with individual applications across a 9.6kbps connection, and yes it was slow and had a bit of lag, but it worked well enough to use xemacs and mozilla across. Also when
<snip> Man, talk about a time traveller! How'd you get a copy of firefox back to when we only had Netscape?
Your right, I started with Mosaic & an "andrew" mail/message program, and moved to Netscape.
Todd Denniston wrote:
John R Pierce wrote, On 10/27/2009 02:42 AM:
GUI over a 28k dialup? ouch. there's no network connection at this remote site? its going to be really really slow over dialup. I'm talking minutes to paint a screen at 2-3kbyte/sec serial speeds (a 1280x1024 24bit desktop is 3.6 million bytes). use a really simple theme on the desktop with no shaded borders, no backgroun graphics ('wallpaper'), etc. Sending a single full screen 1280x1024 photographic image could take a half hour or more.
You Kids and your full desktop hosted back... back in the day I worked with individual applications across a 9.6kbps connection, and yes it was slow and had a bit of lag, but it worked well enough to use xemacs and mozilla across. Also when hosting the application back, you are not transferring all the pixels, but only the X commands to draw them, so unless you are running a picture editor/viewer (such as gimp) then a lot less than your 3.6 million bytes per 1280X1024x24bit will be used. Granted, running the gimp full screen across such a link would be a near insane thing.
I was much happier when I discovered `ssh -C` (in combination with X or Y), to host the apps back. There was still a little lag but overall it was _much_ snappier.
I have yet to use X across a vnc or with freenx so I can't comment on how they compare to `ssh -C`.
The problem with remote X is that it waits until each X command completes before doing anything else. Just opening a new window can take several minutes over a slow link. Vnc isn't particularly efficient, but at least it lets X update at full speed in a frame buffer and decouples the remote redraws. Freenx/nx are much more intelligent, acting as a proxy/cache for X on both ends of the connection so it doesn't force the program to wait and it reuses anything it can that has already been sent when things move around.
But, it's about 25 years too late to find anyone who still knows how to use modems and serial connections. Unix pre-dates tcp networking and had very usable tools which Linux has inherited, but there are good reasons why they aren't used much these days.
John R Pierce wrote:
... over a 28k dialup?
I meant to mention.. Even if your modems are '56k', that only works when a 56k modem dials into a digital modem on a digital trunk line. two '56k' modems dialing each other over conventional analog telephone ("POTS") circuits will get at best 33k, and more likely somewhere between 14k and 28k if the lines are remote and rural.
btw, re someone elses comment about 'you kids'... Would you like to see the old Racal Vadic VA1200 in my junk bin? I think I still have a Courier 2400E, too. The OP has repeatedly stated he wants his full CentOS Desktop, presumably Gnome or KDE, and not just a remote terminal session, or even a X application.
Basically you'll want to use the procedure in the link I posted http://www.howtoforge.com/linux_dialin_server to set up PPP dial-in access. Note that there are a pair of IP addresses in one of the config files, one for each end of the link. On the other side, follow any dial-up internet procedure to get the connection, then you can treat the remote IP address like any other network connection. Dial up network connections are slow, so you actually might prefer to work in command line mode if it is possible for what you need to do. You can do this via ssh over the network. X is designed to work natively over a network but dialup connections are really too slow to use it that way. You might be able to tolerate vnc but freenx and nx would be the best approach for remote GUI access over a low bandwidth link. I'd recommend setting these up and testing over a faster network if you can get two machines together or perhaps use VMware so you know how they are supposed to work. It can be frustrating trying to get this sort of thing working the first time from a remote and slow location.
-Les Mikesell
hadi motamedi wrote:
Thank you very much for your reply . According to your message , the minicom is not suitable in this regard as I really want remote desktop access to my CentOS client located at far site and thus get its keyboard & mouse control to issue commands and view Gui . Please do me favor and propose for the solutions that can enable my CentOS server at the office to get remote desktop access of my CentOS client far at the site (the only connections that can be made is through modem dialup connections) . Let me thank you in advance
On Mon, Oct 26, 2009 at 12:40 PM, Les Mikesell <lesmikesell@gmail.com mailto:lesmikesell@gmail.com> wrote:
hadi motamedi wrote: > Thank you very much for your help . Can you please do me favor and > confirm if the scenario works when both ends are as CentOS (I mean my > CentOS server at the office connected to the telephone line and the > remote CentOS client at the far site that we need to have remote access > to it) ? > Thank you in advance > Running mgetty on the answering side will work with Centos running some dial-out terminal application like kermit, minicom, or cu. But what you'll get is a separate command line login, not a GUI desktop or copy of what is on the console. If you want more than that, you might set up dial-in PPP so you can treat the connection as a network address with all the usual tools. I'm not sure if this is exactly right for Centos but it should be close: http://www.howtoforge.com/linux_dialin_server. Mgetty should be able to detect if you are using dial-up networking from the other end and permit connection either way. -- Les Mikesell lesmikesell@gmail.com <mailto:lesmikesell@gmail.com> _______________________________________________ CentOS mailing list CentOS@centos.org <mailto:CentOS@centos.org> http://lists.centos.org/mailman/listinfo/centos
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hadi motamedi -
John R Pierce -
Les Mikesell -
m.roth＠5-cent.us -
R P Herrold -
Todd Denniston