ESP32 Forum

I experience a problem connecting PPPoS to UBlox SARA-R5.
Tested using ESP-IDF 4.0 and 4.2.

It seems to be a problem with the LCP handshake.

This is the log output directly after receiving 'CONNECT' from module when using ESP-IDF 4.2:

ppp_connect[1]: holdoff=0
ppp phase changed[1]: phase=3
pppos_connect: unit 1: connecting
ppp_start[1]
ppp phase changed[1]: phase=6
pppos_send_config[1]: out_accm=FF FF FF FF
ppp_send_config[1]
pppos_recv_config[1]: in_accm=FF FF FF FF
ppp_recv_config[1]
ppp: auth protocols: PAP=0
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
ppp_start[1]: finished
pppos_input[1]: got 50 bytes
rcvd [LCP ConfReq id=0x0 <asyncmap 0x0> <mru 1500> <auth pap> <accomp> <pcomp>]
No auth is possible
sent [LCP ConfRej id=0x0 <auth pap>]
pppos_write[1]: len=12
pppos_input[1]: got 6 bytes
pppos_input[1]: got 10 bytes
pppos_input[1]: got 12 bytes
pppos_input[1]: got 12 bytes
pppos_input[1]: got 7 bytes
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_input[1]: got 6 bytes
pppos_input[1]: got 11 bytes
rcvd [LCP TermReq id=0x1]
sent [LCP TermAck id=0x1]
pppos_write[1]: len=8
pppos_input[1]: got 2 bytes
pppos_input[1]: Dropping ACCM char <13>
pppos_input[1]: Dropping ACCM char <10>
pppos_input[1]: got 1 bytes
pppos_input[1]: got 11 bytes
pppos_input[1]: Dropping ACCM char <13>
pppos_input[1]: Dropping ACCM char <10>
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x349b0e14> <pcomp> <accomp>]
pppos_write[1]: len=24
LCP: timeout sending Config-Requests
ppp phase changed[1]: phase=12
Connection terminated.
ppp_link_terminated[1]
ppp_link_end[1]
ppp phase changed[1]: phase=0
ppp_link_terminated[1]: finished.

problem solved!
You have to use PAP with empty username and password

Do you have code showing how you were able to do this with the SARA-R5? I've been trying to do it for awhile now. Thanks

I found the solution to get SARA-R5 working.

Enable PAP support in the sdkconfig: LWIP CONFIG_LWIP_PPP_PAP_SUPPORT=y
Set empty user and password for PAP in the modem: AT+UAUTHREQ=1,1,"",""
Set empty user and password on the netif interface: esp_netif_ppp_set_auth(esp_netif_ppp, NETIF_PPP_AUTHTYPE_PAP,"","")


-Rob