Very strange behavior with Linux masquerading and ISDN

Very strange behavior with Linux masquerading and ISDN

Post by Chris Fayl » Tue, 14 May 1996 04:00:00



I am very puzzled by some behavior I've noticed here regarding IP
masquerading and ISDN connections.

I have a local network at home which consists of four machines, three of
which are running Windows and one of which is running Linux 1.99.3.  The
Linux box (mental) acts as a gateway to the outside world either through
a 28.8K modem or via an ISDN link using a BitSurfr PRO.  The other
machines are able to access the outside world because mental is running
IP masquerading.

I have been using this setup with the modem for a month or so with no
problems.  I just switched to ISDN last week.

What I'm seeing is that when mental is connected via ISDN then
connections from the other machines to the rest of the internet are
*extremely* slow.  ftp takes five minutes to login where it took seconds
when mental was connected via the 28.8K modem.

If I cancel the ISDN connection and reinsitute a modem connection then
everything works wonderfully.

Can anyone give me a clue here as to what is going on here?  Obviously
I expected that the connection would be faster with ISDN.
--

Boston Business Computing  \\ VMS=>UNIX Solutions //       the real can be."

 
 
 

Very strange behavior with Linux masquerading and ISDN

Post by Scott Kel » Thu, 16 May 1996 04:00:00



>I am very puzzled by some behavior I've noticed here regarding IP
>masquerading and ISDN connections.
>I have a local network at home which consists of four machines, three of
>which are running Windows and one of which is running Linux 1.99.3.  The
>Linux box (mental) acts as a gateway to the outside world either through
>a 28.8K modem or via an ISDN link using a BitSurfr PRO.  The other
>machines are able to access the outside world because mental is running
>IP masquerading.
>I have been using this setup with the modem for a month or so with no
>problems.  I just switched to ISDN last week.
>What I'm seeing is that when mental is connected via ISDN then
>connections from the other machines to the rest of the internet are
>*extremely* slow.  ftp takes five minutes to login where it took seconds
>when mental was connected via the 28.8K modem.
>If I cancel the ISDN connection and reinsitute a modem connection then
>everything works wonderfully.

Interestingly enough, if you take a look at /etc/rc.d/rc.serial, close
to the bottom of the file you will see something like....

${SETSERIAL} -bg ${PORTS}

What happens is this, you uncomment and modify the entry for your ISDN
modem that is making use of a comm port, but the line above craps it
out and you end up with garbage, comment this puppy out and try this
setting in your entry for the ISDN modem

${SETSERIAL} /dev/cua0 ${AUTO_IRQ} skip_test autoconfig 16550A spd-vhi

For this longest time I could not understand why I was getting so many
packet errors, and in desperation, I looked at my file (DOH!)

- Show quoted text -

>Can anyone give me a clue here as to what is going on here?  Obviously
>I expected that the connection would be faster with ISDN.
>--

>Boston Business Computing  \\ VMS=>UNIX Solutions //       the real can be."


 
 
 

Very strange behavior with Linux masquerading and ISDN

Post by Chris Fayl » Sat, 18 May 1996 04:00:00





>>I am very puzzled by some behavior I've noticed here regarding IP
>>masquerading and ISDN connections.

>>I have a local network at home which consists of four machines, three of
>>which are running Windows and one of which is running Linux 1.99.3.  The
>>Linux box (mental) acts as a gateway to the outside world either through
>>a 28.8K modem or via an ISDN link using a BitSurfr PRO.  The other
>>machines are able to access the outside world because mental is running
>>IP masquerading.

>>I have been using this setup with the modem for a month or so with no
>>problems.  I just switched to ISDN last week.

>>What I'm seeing is that when mental is connected via ISDN then
>>connections from the other machines to the rest of the internet are
>>*extremely* slow.  ftp takes five minutes to login where it took seconds
>>when mental was connected via the 28.8K modem.

>>If I cancel the ISDN connection and reinsitute a modem connection then
>>everything works wonderfully.

>Interestingly enough, if you take a look at /etc/rc.d/rc.serial, close
>to the bottom of the file you will see something like....

>${SETSERIAL} -bg ${PORTS}

>What happens is this, you uncomment and modify the entry for your ISDN
>modem that is making use of a comm port, but the line above craps it
>out and you end up with garbage, comment this puppy out and try this
>setting in your entry for the ISDN modem
>...

I wish it was that simple.  I had noticed the lines in rc.serial and
had commented them out.  In fact, I patched the kernel to understand
the extended fifo in the Hayes serial card.

I'm not getting much packet loss at all with the machine that is directly
connected via PPP.  It is only the masqueraded systems that are suffering.
--

Boston Business Computing  \\ VMS=>UNIX Solutions //       the real can be."

 
 
 

1. Strange ISPELL behaviour using RedHat 5.0 Linux/Alpha

I am a comparative newcomer to Linux and this newsgroup so the question
I have may be common knowledge.

When using ISPELL via the command:
    ispell mary.txt
to check the text file  mary.txt,  two or three pressings of the return
key are
needed to send the spelling selection from the supplied suggestions to
ISPELL.
By comparison, on Linux/Intel only typing the selections number is
required,
ISPELL being able to detect when the selection has been completed.

Maybe there was something wrong with my copy of ISPELL?  So I attempted
to compile two other versions of  ISPELL and in each case the
compilation
ceased in the  term.c  file.  My conclusion is that there is something
strange in the
xterm - ISPELL interconnection that I am using.

Can anybody suggest a solution?
=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
Ross Maloney                         =  voice:  (home) +61 08 9364 1927
                                     +
Graduate Student                     =
School of Computing Science          +

Perth, WA.                           +
AUSTRALIA                            =
=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=

2. help: X - looking for server for i740 video card

3. Internet vs Linux - Strange behavior (Help for a newbie!)

4. Easy "ps" question?

5. Strange trn Behavior Under Linux

6. Logger Q

7. Linux most strange behavior

8. ATI Radeon ve and xwindows 4.1

9. XFree4.2, linux 7.1 strange behaviour

10. Linux Routing/IP Masquerading w/ Cable Modem & ISDN

11. strange LILO behavior w/ Linux on CF

12. Samba(Linux) <-> NT4.0: VERY strange performance behaviour!

13. Compaq Prosignia 150 & Linux & Strange behavior