UDP Port (4729) Conflict Between SIMTrace2 and pySim

Hello community/admin,

I am experiencing an issue while using SIMTrace2 and pySim to sniff and analyze SIM card communication. Below are the details:

---

1. When SIMTrace2 Sniff is Turned Off

I run the following command:

bash
pySim-trace.py gsmtap-udp

Output:

plaintext
Copy code
INFO     root: Opening source gsmtap-udp...
Detected UICC Add-on "SIM"
Detected UICC Add-on "GSM-R"
Detected UICC Add-on "RUIM"
Can't read AIDs from SIM -- 'list' object has no attribute 'lower'
warning: EF.DIR seems to be empty!
ADF.ECASD: a0000005591010ffffffff8900000200
ADF.ISD-R: a0000005591010ffffffff8900000100
ISIM: a0000000871004
USIM: a0000000871002
INFO     root: Entering main loop...

When I check the UDP port (4729) usage:

bash
sudo lsof -i :4729

Output:

plaintext
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
python3 198340  jun    4u  IPv4 301846      0t0  UDP localhost:4729

---

2. When SIMTrace2 Sniff is Turned On

I run the following command:

bash
simtrace2-sniff

Output:

plaintext
simtrace2-sniff - Phone-SIM card communication sniffer
(C) 2010-2017 by Harald Welte <laforge@gnumonks.org>
(C) 2018 by Kevin Redon <kredon@sysmocom.de>

Using USB device 1d50:60e3 Addr=46, Path=1-5, Cfg=1, Intf=0, Alt=0: 255/1/0 (SIMtrace Sniffer)
Entering main loop
ATR: 3b 9f 96 80 1f c7 80 31 e0 73 fe 21 11 57 86 81 27 86 98 60 58 ec
PPS: ff 00 ff 
TPDU: a0 a4 00 00 02 7f 20 9f 17 
TPDU: a0 c0 00 00 17 00 00 00 00 7f 20 02 00 00 00 00 00 0a 93 00 1c 04 00 83 8a 83 8a 00 90 00

When I check the UDP port (4729) usage:

bash
sudo lsof -i :4729

Output:

plaintext
COMMAND      PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
simtrace2 198351  jun    7u  IPv4 308389      0t0  UDP localhost:36190->localhost:4729
simtrace2 198351  jun    8u  IPv4 308390      0t0  UDP localhost:4729

---

UDP Port (4729) Conflict Between SIMTrace2 and pySim

Hello community/admin,

I am experiencing an issue while using SIMTrace2 and pySim to sniff and analyze SIM card communication. Below are the details:

---

1. When SIMTrace2 Sniff is Turned Off

I run the following command:

bash
Copy code
/usr/src/pysim/pySim-trace.py gsmtap-udp

Output:

plaintext
Copy code
INFO     root: Opening source gsmtap-udp...
Detected UICC Add-on "SIM"
Detected UICC Add-on "GSM-R"
Detected UICC Add-on "RUIM"
Can't read AIDs from SIM -- 'list' object has no attribute 'lower'
warning: EF.DIR seems to be empty!
ADF.ECASD: a0000005591010ffffffff8900000200
ADF.ISD-R: a0000005591010ffffffff8900000100
ISIM: a0000000871004
USIM: a0000000871002
INFO     root: Entering main loop...

When I check the UDP port (4729) usage:

bash
sudo lsof -i :4729

Output:

plaintext
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
python3 198340  jun    4u  IPv4 301846      0t0  UDP localhost:4729

---

2. When SIMTrace2 Sniff is Turned On

I run the following command:

bash
simtrace2-sniff

Output:

plaintext
simtrace2-sniff - Phone-SIM card communication sniffer
(C) 2010-2017 by Harald Welte <laforge@gnumonks.org>
(C) 2018 by Kevin Redon <kredon@sysmocom.de>

Using USB device 1d50:60e3 Addr=46, Path=1-5, Cfg=1, Intf=0, Alt=0: 255/1/0 (SIMtrace Sniffer)
Entering main loop
ATR: 3b 9f 96 80 1f c7 80 31 e0 73 fe 21 11 57 86 81 27 86 98 60 58 ec
PPS: ff 00 ff 
TPDU: a0 a4 00 00 02 7f 20 9f 17 
TPDU: a0 c0 00 00 17 00 00 00 00 7f 20 02 00 00 00 00 00 0a 93 00 1c 04 00 83 8a 83 8a 00 90 00

When I check the UDP port (4729) usage:

bash
sudo lsof -i :4729

Output:

plaintext
COMMAND      PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
simtrace2 198351  jun    7u  IPv4 308389      0t0  UDP localhost:36190->localhost:4729
simtrace2 198351  jun    8u  IPv4 308390      0t0  UDP localhost:4729

---

3. When Running SIMTrace2 Sniff and pySim-trace.py Together

If I try to run both SIMTrace2 sniff and pySim-trace.py gsmtap-udp simultaneously, I get the following error from pySim:

plaintext
jun@jun-RDR:pySim-trace.py gsmtap-udp
INFO     root: Opening source gsmtap-udp...
Traceback (most recent call last):
  File "pySim-trace.py", line 199, in <module>
    s = GsmtapApduSource(opts.bind_ip, opts.bind_port)
  File "pysim/pySim/apdu_source/gsmtap.py", line 44, in __init__
    self.gsmtap = GsmtapReceiver(bind_ip, bind_port)
  File "/home/jun/.local/lib/python3.10/site-packages/osmocom/gsmtap.py", line 207, in __init__
    self.sock.bind((self.bind_ip, self.bind_port))
OSError: [Errno 98] Address already in use

---

Main Issue

1. When SIMTrace2 sniff is running, it occupies UDP port 4729, preventing pySim from using the same port.
2. When SIMTrace2 sniff is stopped, pySim can access UDP port 4729 but fails to decode data, showing the following errors:

   plaintext
   Can't read AIDs from SIM -- 'list' object has no attribute 'lower'
   warning: EF.DIR seems to be empty!
   

3. If I try to run both tools at the same time, pySim crashes with the error [Errno 98] Address already in use.

---

Request for Help

• Has anyone experienced a similar issue when running SIMTrace2 and pySim together?
• How can I avoid the port conflict and ensure both tools can run simultaneously?
• What could cause the decoding error and the warning about an empty EF.DIR in pySim?

Any insights or advice would be greatly appreciated. Thank you!