*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 &lt;laforge(a)gnumonks.org&gt; (C) 2018 by Kevin Redon &lt;kredon(a)sysmocom.de&gt; 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 &lt;laforge(a)gnumonks.org&gt; (C) 2018 by Kevin Redon &lt;kredon(a)sysmocom.de&gt; 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!