How to fix continuous ConfReq's on celluar internet connection

[Marshall Crocker <mcrocker@123mail.org>]

Hi all,

For over a year now I've been having problems with ConfReq's resetting 
my ppp connection to my cellular EvDO internet provider.  I can connect 
with no problems but usually the connection will only stay up for a few 
minutes (sometimes a few seconds) before I receive a ConfReq.  I think 
the ConfReq is sent because I'm in a fringe area of service and my 
connection is switching between EvDO (3G broadband speeds) and 1xRTT 
(144 Kbps 2.5G).  It may also be that I'm between two towers and the 
connection is bouncing between the two thereby requiring my host to 
reconfigure.

The biggest problem with this behavior is that the ppp0 interface is 
brought down after the ConfReq is received.  Any TCP connections that 
were in progress get closed.  In Windows, the connection is reconfigured 
but either the interface isn't completely brought down or a "no route to 
host" isn't sent  for each open connection and the packets just get 
dropped during the reconfigure and then retransmitted once the 
connection comes back up so actions such as browsing  web pages only get 
stalled briefly.

So my questions are

1) Has anyone else seen this behavior or is it specific to my internet 
provider?

2) Is there some pppd option that I'm missing that could solve this problem?

3) Should I block these ConfReq's once the connection is established 
using iptables or some other method?  I assume not since the tower may 
drop my connection if my host doesn't respond.

4) Maybe I could hack pppd to not bring the connection down during 
reconfiguration/reauthenication if the connection details are the same 
(i.e. same local and ptp ip addresses, same dns, etc. )?

I know there is a firmware update to my EvDO card (a Kyocera KPC650) 
which will allow you to "lock" in a tower and technology (EvDO or 1xRTT) 
but I don't think it will work in linux unless the KPC650 command and 
control protocol has been decoded.  It may be possible to do the "lock" 
from the windows client and then the card stays locked but I don't know.

Any help is greatly appreciated as I have been stuck using XP and ICS 
instead of putting my EvDO card in my soekris router.

Below is a snip from the pppd debug log.  I can also provide the windows 
ppp log if that would help.

Thanks,
Marshall

local  IP address X.X.X.X
 remote IP address X.X.X.X
 primary   DNS address X.X.X.X
 secondary DNS address X.X.X.X
 Script /etc/ppp/ip-up started (pid 15676)
 Script /etc/ppp/ip-up finished (pid 15676), status = 0x1
 rcvd [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0xdd5ce74b>]
 Connect time 0.3 minutes.
 Sent 1115 bytes, received 778 bytes.
 Script /etc/ppp/ip-down started (pid 15685)
 sent [LCP ConfReq id=0x8e <asyncmap 0x0> <magic 0x6a4b56c2> <pcomp> 
<accomp>]
 sent [LCP ConfAck id=0x1 <asyncmap 0x0> <auth pap> <magic 0xdd5ce74b>]
 rcvd [LCP ConfAck id=0x8e <asyncmap 0x0> <magic 0x6a4b56c2> <pcomp> 
<accomp>]
 sent [LCP EchoReq id=0x0 magic=0x6a4b56c2]
 sent [PAP AuthReq id=0xb2 user="XXXXX@cs3g.com" password=<hidden>]
 Script /etc/ppp/ip-down finished (pid 15685), status = 0x0
 rcvd [LCP EchoRep id=0x0 magic=0xdd5ce74b]
 rcvd [PAP AuthAck id=0xb2 ""]
 PAP authentication succeeded
 sent [IPCP ConfReq id=0x57 <compress VJ 0f 01> <addr X.X.X.X> <ms-dns1 
0.0.0.0> <ms-dns3 0.0.0.0>]
 rcvd [IPCP ConfReq id=0x1 <addr X.X.X.X>]
 sent [IPCP ConfAck id=0x1 <addr X.X.X.X>]
 rcvd [IPCP ConfRej id=0x57 <compress VJ 0f 01>]
sent [IPCP ConfReq id=0x58 <addr X.X.X.X> <ms-dns1 0.0.0.0> <ms-dns3 
0.0.0.0>]
 rcvd [IPCP ConfNak id=0x58 <ms-dns1 X.X.X.X> <ms-dns3 X.X.X.X>]
 sent [IPCP ConfReq id=0x59 <addr X.X.X.X> <ms-dns1 X.X.X.X> <ms-dns3 
X.X.X.X>]
 rcvd [IPCP ConfAck id=0x59 <addr X.X.X.X> <ms-dns1 X.X.X.X> <ms-dns3 
X.X.X.X>]
 Cannot determine ethernet address for proxy ARP
 local  IP address X.X.X.X
 remote IP address X.X.X.X
 primary   DNS address X.X.X.X
 secondary DNS address X.X.X.X
 Script /etc/ppp/ip-up started (pid 15691)
 Script /etc/ppp/ip-up finished (pid 15691), status = 0x1