[GH-ISSUE #1636] SyslogUDPHandler not working #695

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opened 2026-03-04 02:17:07 +03:00 by kerem · 0 comments

kerem commented

2026-03-04 02:17:07 +03:00

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Originally created by @CyberLine on GitHub (Feb 22, 2022).
Original GitHub issue: https://github.com/Seldaek/monolog/issues/1636

Monolog version 2.3.5

When i tried to switch from SyslogHandler to SyslogUdpHandler, nothing happens in rsyslog side.
TCPdump gives me the following checksum error:

tcpdump -i lo udp port 514 -vvv
tcpdump: listening on lo, link-type EN10MB (Ethernet), snapshot length 262144 bytes
16:23:10.948933 IP (tos 0x0, ttl 64, id 8538, offset 0, flags [DF], proto UDP (17), length 442)
    localhost.localdomain.58202 > localhost.localdomain.syslog: [bad udp cksum 0xffb9 -> 0x94a7!] SYSLOG, length: 414
        Facility daemon (3), Severity debug (7)
        Msg: 1 2022-02-22T16:23:10+01:00 alexander logstash 134538 - - {"@timestamp":"2022-02-22T16:23:10.948691+01:00","@version":1,"host":"alexander","message":"ping","type":"app","channel":"app","level":"DEBUG","monolog_level":100,"extra":{"process_id":134538,"node":"alexander","url":"/ping","ip":"127.0.0.1","http_method":"GET","server":"localhost","referrer":null}}^J

(i have replaced some values in json to be posted here, but the original payload has 414 bytes)

Originally created by @CyberLine on GitHub (Feb 22, 2022). Original GitHub issue: https://github.com/Seldaek/monolog/issues/1636 Monolog version 2.3.5 When i tried to switch from SyslogHandler to SyslogUdpHandler, nothing happens in rsyslog side. TCPdump gives me the following checksum error: ``` tcpdump -i lo udp port 514 -vvv tcpdump: listening on lo, link-type EN10MB (Ethernet), snapshot length 262144 bytes 16:23:10.948933 IP (tos 0x0, ttl 64, id 8538, offset 0, flags [DF], proto UDP (17), length 442) localhost.localdomain.58202 > localhost.localdomain.syslog: [bad udp cksum 0xffb9 -> 0x94a7!] SYSLOG, length: 414 Facility daemon (3), Severity debug (7) Msg: 1 2022-02-22T16:23:10+01:00 alexander logstash 134538 - - {"@timestamp":"2022-02-22T16:23:10.948691+01:00","@version":1,"host":"alexander","message":"ping","type":"app","channel":"app","level":"DEBUG","monolog_level":100,"extra":{"process_id":134538,"node":"alexander","url":"/ping","ip":"127.0.0.1","http_method":"GET","server":"localhost","referrer":null}}^J ``` (i have replaced some values in json to be posted here, but the original payload has 414 bytes)