Here is the output. I‘m wondering why systemd is listening on port 6556 on IPv6? Shouldn‘t that be done from xinetd?
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
systemd 1 root cwd DIR 8,1 4096 2 /
systemd 1 root rtd DIR 8,1 4096 2 /
systemd 1 root txt REG 8,1 1739200 396983 /usr/lib/systemd/systemd
systemd 1 root mem REG 8,1 149576 397152 /usr/lib/x86_64-linux-gnu/libgpg-error.so.0.29.0
systemd 1 root mem REG 8,1 3076960 395736 /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1
systemd 1 root mem REG 8,1 26984 393551 /usr/lib/x86_64-linux-gnu/libcap-ng.so.0.0.0
systemd 1 root mem REG 8,1 617128 397608 /usr/lib/x86_64-linux-gnu/libpcre2-8.so.0.10.1
systemd 1 root mem REG 8,1 149520 394670 /usr/lib/x86_64-linux-gnu/libpthread-2.31.so
systemd 1 root mem REG 8,1 18688 394659 /usr/lib/x86_64-linux-gnu/libdl-2.31.so
systemd 1 root mem REG 8,1 158400 398003 /usr/lib/x86_64-linux-gnu/liblzma.so.5.2.5
systemd 1 root mem REG 8,1 890800 399431 /usr/lib/x86_64-linux-gnu/libzstd.so.1.4.8
systemd 1 root mem REG 8,1 137568 394172 /usr/lib/x86_64-linux-gnu/liblz4.so.1.9.3
systemd 1 root mem REG 8,1 35280 393740 /usr/lib/x86_64-linux-gnu/libip4tc.so.2.0.0
systemd 1 root mem REG 8,1 1176248 397239 /usr/lib/x86_64-linux-gnu/libgcrypt.so.20.2.8
systemd 1 root mem REG 8,1 202680 394648 /usr/lib/x86_64-linux-gnu/libcrypt.so.1.1.0
systemd 1 root mem REG 8,1 38864 394213 /usr/lib/x86_64-linux-gnu/libcap.so.2.44
systemd 1 root mem REG 8,1 326624 394781 /usr/lib/x86_64-linux-gnu/libblkid.so.1.1.0
systemd 1 root mem REG 8,1 38936 394931 /usr/lib/x86_64-linux-gnu/libacl.so.1.1.2253
systemd 1 root mem REG 8,1 1839792 394658 /usr/lib/x86_64-linux-gnu/libc-2.31.so
systemd 1 root mem REG 8,1 76480 395336 /usr/lib/x86_64-linux-gnu/libapparmor.so.1.6.3
systemd 1 root mem REG 8,1 108592 398721 /usr/lib/x86_64-linux-gnu/libkmod.so.2.3.6
systemd 1 root mem REG 8,1 128952 393557 /usr/lib/x86_64-linux-gnu/libaudit.so.1.0.0
systemd 1 root mem REG 8,1 67584 395960 /usr/lib/x86_64-linux-gnu/libpam.so.0.85.1
systemd 1 root mem REG 8,1 375424 394792 /usr/lib/x86_64-linux-gnu/libmount.so.1.1.0
systemd 1 root mem REG 8,1 166120 398475 /usr/lib/x86_64-linux-gnu/libselinux.so.1
systemd 1 root mem REG 8,1 137536 394072 /usr/lib/x86_64-linux-gnu/libseccomp.so.2.5.1
systemd 1 root mem REG 8,1 39912 394672 /usr/lib/x86_64-linux-gnu/librt-2.31.so
systemd 1 root mem REG 8,1 2692512 396805 /usr/lib/systemd/libsystemd-shared-247.so
systemd 1 root mem REG 8,1 177928 394654 /usr/lib/x86_64-linux-gnu/ld-2.31.so
systemd 1 root 0u CHR 1,3 0t0 4 /dev/null
systemd 1 root 1u CHR 1,3 0t0 4 /dev/null
systemd 1 root 2u CHR 1,3 0t0 4 /dev/null
systemd 1 root 3w CHR 1,11 0t0 10 /dev/kmsg
systemd 1 root 4u a_inode 0,13 0 9074 [eventpoll]
systemd 1 root 5u a_inode 0,13 0 9074 [signalfd]
systemd 1 root 6r a_inode 0,13 0 9074 inotify
systemd 1 root 7r DIR 0,25 0 1 /sys/fs/cgroup
systemd 1 root 8u a_inode 0,13 0 9074 [timerfd]
systemd 1 root 9u a_inode 0,13 0 9074 [eventpoll]
systemd 1 root 10r REG 0,20 0 175 /proc/1/mountinfo
systemd 1 root 11r a_inode 0,13 0 9074 inotify
systemd 1 root 13r a_inode 0,13 0 9074 inotify
systemd 1 root 14r REG 0,20 0 4026532069 /proc/swaps
systemd 1 root 15u netlink 0t0 176 KOBJECT_UEVENT
systemd 1 root 16u unix 0x000000008c430a9f 0t0 177 /run/systemd/notify type=DGRAM
systemd 1 root 17u unix 0x000000008a9695fd 0t0 178 type=DGRAM
systemd 1 root 18u unix 0x000000005c8c7057 0t0 179 type=DGRAM
systemd 1 root 19u unix 0x000000007ec1114e 0t0 180 /run/systemd/private type=STREAM
systemd 1 root 20u unix 0x000000001f0fb1f3 0t0 182 /run/systemd/userdb/io.systemd.DynamicUser type=STREAM
systemd 1 root 21u unix 0x00000000fc6e71a2 0t0 183 /run/systemd/io.system.ManagedOOM type=STREAM
systemd 1 root 25u unix 0x00000000059d3cc8 0t0 683267 /run/systemd/journal/stdout type=STREAM
systemd 1 root 26r a_inode 0,13 0 9074 inotify
systemd 1 root 27r a_inode 0,13 0 9074 inotify
systemd 1 root 28r CHR 10,235 0t0 235 /dev/autofs
systemd 1 root 29r FIFO 0,12 0t0 190 pipe
systemd 1 root 30u a_inode 0,13 0 9074 [timerfd]
systemd 1 root 31u unix 0x00000000029c4251 0t0 193 /run/systemd/journal/syslog type=DGRAM
systemd 1 root 32u unix 0x00000000a5ee56e4 0t0 195 /run/systemd/fsck.progress type=STREAM
systemd 1 root 33u FIFO 0,22 0t0 247 /run/initctl
systemd 1 root 34u netlink 0t0 198 AUDIT
systemd 1 root 35u unix 0x00000000eee88933 0t0 199 /run/systemd/journal/dev-log type=DGRAM
systemd 1 root 36u unix 0x000000002b72fe33 0t0 201 /run/systemd/journal/socket type=DGRAM
systemd 1 root 37u unix 0x00000000c7d322c2 0t0 203 /run/systemd/journal/stdout type=STREAM
systemd 1 root 38u unix 0x00000000bb07841c 0t0 205 /run/udev/control type=SEQPACKET
systemd 1 root 39u netlink 0t0 207 KOBJECT_UEVENT
systemd 1 root 40u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 41u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 42u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 43u netlink 0t0 253 AUDIT
systemd 1 root 44u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 45u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 46u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 47u unix 0x00000000b01391ba 0t0 352 type=DGRAM
systemd 1 root 48u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 49u unix 0x00000000f1ff1fb3 0t0 12271 /run/systemd/journal/stdout type=STREAM
systemd 1 root 50u unix 0x000000000e4aac5f 0t0 746 /run/systemd/journal/stdout type=STREAM
systemd 1 root 51u unix 0x0000000007ea1bb1 0t0 383 /run/systemd/journal/stdout type=STREAM
systemd 1 root 52u a_inode 0,13 0 9074 [timerfd]
systemd 1 root 53u unix 0x000000009f91d42b 0t0 11762 /run/dbus/system_bus_socket type=STREAM
systemd 1 root 54u IPv6 11761 0t0 TCP *:6556 (LISTEN)
systemd 1 root 55u unix 0x000000000eef3013 0t0 11732 /run/systemd/journal/stdout type=STREAM
systemd 1 root 56u unix 0x00000000c5b3389e 0t0 11764 /run/pcscd/pcscd.comm type=STREAM
systemd 1 root 57u unix 0x00000000391f8838 0t0 11773 type=STREAM
systemd 1 root 58u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 59u unix 0x00000000d386092b 0t0 11863 /run/systemd/journal/stdout type=STREAM
systemd 1 root 60u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 61u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 62u a_inode 0,13 0 9074 bpf-prog
systemd 1 root 63u unix 0x00000000b2e4cbed 0t0 11774 /run/systemd/journal/stdout type=STREAM
systemd 1 root 64u unix 0x00000000cea4b78a 0t0 11775 /run/systemd/journal/stdout type=STREAM
systemd 1 root 66u unix 0x000000005f9816cc 0t0 11798 /run/systemd/journal/stdout type=STREAM
systemd 1 root 67u unix 0x00000000778d1f62 0t0 682 /run/systemd/journal/stdout type=STREAM
systemd 1 root 69u unix 0x0000000078a77f81 0t0 769 /run/systemd/journal/stdout type=STREAM
systemd 1 root 71u unix 0x000000009cde92c8 0t0 756 /run/systemd/journal/stdout type=STREAM