this post was submitted on 16 Aug 2023
35 points (97.3% liked)

Linux

48313 readers
713 users here now

From Wikipedia, the free encyclopedia

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

Rules

Related Communities

Community icon by Alpár-Etele Méder, licensed under CC BY 3.0

founded 5 years ago
MODERATORS
AgreeableLandscape@lemmy.ml
nooter692@lemmy.ml
MarcellusDrum@lemmy.ml
cypherpunks@lemmy.ml
cyclohexane@lemmy.ml
d3Xt3r
35
No route to host until I ping and then it works fine? (self.linux)
submitted 1 year ago* (last edited 1 year ago) by luthis to c/linux@lemmy.ml
21 comments fedilink hide all child comments
 

Probably should find a linux networking specific community for this one..

I have a strange issue that feels very familiar, like I've fixed it before, but I can't remember how.

I try to rtsp to security cam:

ffplay rtsp://user:password@192.168.19.137:554/h264Preview_01_main

And I get a no route:

Connection to tcp://192.168.19.137:554?timeout=0 failed: No route to host

rtsp://user:password@192.168.19.137:554/h264Preview_01_main: No route to host

Strange, I'm in the same subnet 192.168.19.129/24, and it worked a few days ago.

Check ping:

ping 192.168.19.137

PING 192.168.19.137 (192.168.19.137) 56(84) bytes of data.

64 bytes from 192.168.19.137: icmp_seq=1 ttl=64 time=5.69 ms

Of course.. So I run the command again;

ffplay rtsp://user:password@192.168.19.137:554/h264Preview_01_main

And now it works.

I could bandaid by crontabbing a ping every hour or something, but I would really like to know why I'm getting a 'no route' until I ping.

My routing table is pretty basic:

default via 192.168.19.1 dev enp4s0 proto dhcp src 192.168.19.129 metric 100

default via 192.168.19.1 dev enp4s0 proto dhcp src 192.168.19.129 metric 1002

172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown

172.18.0.0/16 dev br-68c1e0344e27 proto kernel scope link src 172.18.0.1 linkdown

192.168.19.0/24 dev enp4s0 proto dhcp scope link src 192.168.19.129 metric 1002

192.168.19.1 dev enp4s0 proto dhcp scope link src 192.168.19.129 metric 1024

And I don't think I have any rules in firewall for LAN.

Any ideas?

you are viewing a single comment's thread
view the rest of the comments
[–] empireOfLove@lemmy.one 25 points 1 year ago (1 children)

Are you sure the camera is not going into some kind of low power sleep mode and then has a wake-on-LAN functionality that only responds to icmp/magic packets? The number of embedded devices that have aggressive power saving measures built in is kinda stupid tbh.

Can you reliably rtsp from a different machine to rule out the routing table?

[–] luthis 7 points 1 year ago (2 children)

I can try test that.

The camera is always accessible via the android app, but that's not quite the same.

[–] empireOfLove@lemmy.one 10 points 1 year ago

The android app, if proprietary and manufacturer specific, could very well be sending its own magic wake-on-lan packet to check if the camera is alive.

I unfortunately don't know enough about nitty-gritty networking stuff to help with the actual routing though, refer to the other commenters for that.

[–] blattrules@lemmy.world 7 points 1 year ago

This is what I thought it sounded like too. I’ve seen similar behavior with wake on lan before.