Public IPv4 for app in cdg routes through nrt, causing 900ms+ latency

1

Hi Fly team,

I’m seeing very high latency for my API hosted on Fly.

App: `paytix-lu-api`
Custom domain: `api.paytix.lu`
Fly hostname: `paytix-lu-api.fly.dev`
Public IPv4: `66.51.126.67`
Primary region: `cdg`
Client location: Luxembourg / nearby EU

My machines are running in `cdg`

However, requests to https://api.paytix.lu/ are consistently very slow from Luxembourg:

curl total: ~930-1050ms

TCP connect: ~230-250ms

TLS complete: ~460-490ms

TTFB: ~930-1050ms

ping avg: ~226ms

Example curl result:

http_code=200

dns=0.002s

connect=0.244s

tls=0.484s

ttfb=0.948s

total=0.949s

remote=66.51.126.67

The response headers include a Fly request ID ending in nrt, for example:

fly-request-id: 01KWM57Z224HQZ9DFH0W4TDV9M-nrt

via: 2 fly.io, 2 fly.io

The route itself is trivial and returns a small JSON response, so this does not appear to be application/database latency.

Could you check whether the public IPv4 66.51.126.67 is being incorrectly routed through/near nrt instead of a European edge? Should I allocate a new IPv4, or can this routing be fixed on Fly’s side?

Thanks!

2

Could you identify your local ISP so that we can tune the route better? We will need at least the name of your ISP in order to be able to make any adjustments. Ideally, also run a traceroute or mtr to the public IPv4 in question to help us identify where the route went wrong here.

3

Sure, thanks for you fast reply.

My local ISP is “POST Luxembourg”

traceroute to 66.51.126.67 (66.51.126.67), 20 hops max, 40 byte packets

 1  192.168.178.1  34.202 ms  1.544 ms  1.416 ms

 2  100.104.32.1  11.741 ms  6.907 ms  9.327 ms

 3  * * *

 4  * 184.104.204.241  44.607 ms *

 5  72.52.92.70  46.101 ms  21.441 ms *

 6  184.105.80.179  17.163 ms  10.075 ms  10.915 ms

 7  184.104.193.43  233.946 ms  227.693 ms  227.705 ms

 8  * * *

 9  * * *

10  * 184.104.199.10  237.430 ms *

11  203.190.230.209  223.452 ms  223.633 ms  228.239 ms

12  * * 79.127.194.99  224.933 ms

13  * * *

14  * * *

15  * * *

16  * * *

17  *

The useful result is already captured: latency jumps at hop 7 from ~10-17ms to ~228-234ms,

Thanks!