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The port was frozen at 514 in the call that opens the connection, so a collector listening anywhere else was simply out of reach, and plenty do, because 514 is privileged and containerised collectors usually get a high port instead. Working around it meant putting a proxy in front, which then rewrites the source address and hides which device actually sent the line. Add `syslog port <n>`. The default stays 514, so nothing changes for an existing configuration. Setting it tears the connection down and builds a new one, the same dance the address already does, because uip_udp_new() freezes the port into the connection. The value is parsed here rather than through atoi_short(), which reports "no digits" but not overflow: 65540 would quietly wrap to 4 and we would open a connection to a port nobody asked for. Checking before each multiply keeps it in 16-bit arithmetic. Zero then covers all three ways to be wrong - no digits, past 65535, or an explicit "0", which is not a port either. Whitelist the new command in config.js as well, next to `syslog ip`, or the line is dropped without a word when the configuration is saved and the setting quietly fails to survive a reboot. The dedup entry has to precede the general `^syslog\b` one, otherwise it would deduplicate against `syslog on`. itoa_short() is new: itoa() only handles a byte and print_short() prints hex, so there was no way to show a port as a decimal number. Kept separate from itoa() rather than widening it, because every existing caller passes a byte and would start paying for 16-bit divisions it does not need. The scratch variables for the parser live in xdata. Locals there would take internal RAM, and this image has none left: data ends at 0x77, the overlay occupies 0x78-0x7f and the stack starts at 0x80. Measured: no module's DSEG grew.
