Rewriting Host tailing dots in logs

Help!
1

I have a haproxy 1.5.18 setup and some users came with tailing dot in hostname
for example “domain.com.”
i cut tailing dot with

http-request replace-value Host (.*). \1

it goes normal to backend servers
but in log file it’s still comes as “domain.com.”

i use

capture request header Host len 20
log-format %[capture.req.hdr(0),lower]\
2

I think you should issue http-request replace-value ... before capture request header Host...

BTW, the regular expression should escape the last dot. (Perhaps as in \\.?)

3

Yes, capture request placed under replace-value

...
  http-request replace-value Host (.*). \1
  http-request add-header X-Real-IP %[src]
  # redirect users if no SSL used
  redirect scheme https code 301 if !{ ssl_fc }
  default_backend bk_nginx
  option clitcpka

  # logging
  capture request  header Host len 200
  log-format %[capture.req.hdr(0),lower]\ 
...
4

Make sure that the new Host header value actually has the final . removed. As said earlier I would fiddle with the regular expression.

Based on the manual example bellow:

http-request replace-value X-Forwarded-For ^192\.168\.(.*)$ 172.16.\1

I would say that your regular expression should in fact be ^(.*)\.$

5 
^(.*)\.$ works as well as my (.*).

tcpdumping to backend shows

...
User-Agent: rrr
Host: domain.com
Accept: */*
...

and that’s ok
but in log file appears original Host domain.com. with final dot

6

Try to use http-request capture req.fhdr(Host)

7

This command is unsupported under 1.5.18

8

Then unfortunately there isn’t much you can do…

Perhaps try to see if there isn’t regsub transformer support, in which case you could write log-format %[capture.req.hdr(0),lower,regsub(^(.*)\.$,\1)]