Gentoo Archives: gentoo-user

From: Grant <emailgrant@×××××.com>
To: Gentoo mailing list <gentoo-user@l.g.o>
Subject: Re: [gentoo-user] Re: {OT} ISP requires MTU below 1500?
Date: Wed, 21 Sep 2016 17:43:51
Message-Id: CAN0CFw30HvN5O17EwNLEgQ_EDnhypH231xUH5nfajq7fqk7XGA@mail.gmail.com
In Reply to: Re: [gentoo-user] Re: {OT} ISP requires MTU below 1500? by Grant
1 >> Maybe run a ping to a destination which you are having problems with,
2 >> then reproduce the problem (with the network idle otherwise). You should
3 >> see ping packets dropped only then.
4 >>
5 >> You can also ping with increasing packet sizes (see ping --help) and
6 >> see when the packet becomes too big for path MTU. But instead lowering
7 >> your MTU then, you should allow icmp-fragmentation-needed come through
8 >> reliably. Lowering MTU only makes sense to stop overly fragmentation in
9 >> the first place and optimize for a specific packet path (like traffic
10 >> through one or multiple VPN tunnels) where fragmentation would
11 >> otherwise increase latency a lot, or where icmp-frag-needed does not
12 >> correctly work.
13 >
14 >
15 > I'll try pinging today once the issue pops up.
16
17
18 I'm seeing the issue again as usual but ping response times come back
19 normal at about 50ms. I'll keep trying.
20
21 - Grant

Replies

Subject Author
[gentoo-user] Re: {OT} ISP requires MTU below 1500? Kai Krakow <hurikhan77@×××××.com>