So I was browsing my HAProxy logs earlier today and noticed some odd requests being made by external IP addresses to domains that we are not hosting.
For example
Jun 8 06:25:56 haproxy haproxy[6316]: 185.108.107.19:54243 [08/Jun/2020:06:25:56.731] localhost localhost/<NOSRV> -1/-1/-1/-1/13 503 213 - - SC-- 2/2/0/0/0 0/0 "CONNECT chekfast.zennolab.com:443 HTTP/1.1
Jun 8 06:26:33 haproxy haproxy[6316]: 185.108.107.19:54598 [08/Jun/2020:06:26:33.855] localhost localhost/<NOSRV> -1/-1/-1/-1/3 400 188 - - PR-- 0/0/0/0/0 0/0 "<BADREQ>"
Jun 8 06:34:07 haproxy haproxy[6316]: 94.200.76.222:55958 [08/Jun/2020:06:34:07.906] localhost localhost/<NOSRV> -1/-1/-1/-1/0 503 213 - - SC-- 0/0/0/0/0 0/0 "POST /cgi-bin/mainfunction.cgi HTTP/1.1"
Jun 8 06:46:05 haproxy haproxy[6316]: 14.221.172.38:2184 [08/Jun/2020:06:46:05.845] localhost localhost/<NOSRV> -1/-1/-1/-1/11 503 213 - - SC-- 6/6/0/0/0 0/0 "GET http://api.gxout.com/proxy/check.aspx HTTP/1.1"
Jun 8 06:59:49 haproxy haproxy[6316]: 223.12.75.250:17883 [08/Jun/2020:06:59:49.392] localhost localhost/<NOSRV> -1/-1/-1/-1/0 503 213 - - SC-- 11/11/0/0/0 0/0 "HEAD http://123.125.114.144/ HTTP/1.1"
From what I can tell the person doing this (or script) is getting response codes like 503 (Service Unavailable) which I am hoping means that the request is not going through properly - but is there some way I can stop these sorts of requests from being made in the first place? We are running HAProxy version 1.6.3 on Ubuntu 16.04.4 LTS.
Thanks