Monitoring IP addresses

Igor Verentsov

Access for monitoring checks

Add these to your firewall allow-list so our checks are not mistaken for unwanted traffic. The list is machine-readable, so a rule can be built by a script rather than by email.

Our main vantage point

IPv4

81.163.20.249
Russia, Moscow ru-msk

Last changed: 2026-09-16

Last confirmed by measurement: 2026-10-10.

/en/monitoring-ips.txt

one address per line, comments start with #.

Open TXT

IPv6 is not used: all checks go out over IPv4.

Our regional probes

Machines we run ourselves, one per country. These addresses are ours, so we publish them: a check arriving from one of them is ours.

38.180.26.199 Dubai, AE own-ae
38.180.128.164 Sydney, AU own-au
38.180.220.165 Sao Paulo, BR own-br
149.33.52.190 Frankfurt am Main, DE own-de
38.180.148.240 Tokyo, JP own-jp
38.180.74.244 Singapore, SG own-sg
38.180.138.136 New York, US own-us

Backup regions, via check-host.net

Our own nodes are listed above: the Moscow server and the regional probes we run ourselves. Where we have no probe of our own, checks fall back to check-host.net nodes — that pool does not belong to us, it changes between checks, and we cannot promise it will stay the same tomorrow.

No fixed IP list

Why we do not publish these addresses

Publishing those addresses would mean promising someone else’s infrastructure. An allow-list that works most of the time is worse than none: it looks like it works.

ru-spb Russia (St. Petersburg) check-host.net
eu-de Germany check-host.net
us-east USA (East) check-host.net
ap-sg Singapore (Asia) check-host.net
eu-nl Netherlands check-host.net

How the checks look from your side

ICMP Ping

Ping is a plain ICMP Echo Request (three packets, five-second timeout) — not a TCP probe dressed up as a ping.

DNS resolution

We ping the address the name resolved to, not the name itself. This is deliberate — it closes DNS rebinding — and it has a side effect worth knowing: with several A-records, one check hits one address, not all of them.

HTTP checks

HTTP checks arrive with the User-Agent of our monitor, so they are easy to tell apart in your logs.