Date: Mon, 23 Mar 2020 12:00:12 +0700 From: Victor Sudakov <vas@sibptus.ru> To: freebsd-net@freebsd.org Subject: IP MTU on gif and gre interfaces (with and without IPSec encryption) Message-ID: <20200323050012.GA50490@admin.sibptus.ru>
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[-- Attachment #1 --] Dear Colleagues, If the MTU on the external Ethernet interface is 1500, it should be safe to configure the gif(4) interfaces with mtu=1480 and gre(4) interfaces with mtu=1476, correct? I've noticed that a newly created gre0 interface has the expected "mtu 1476" value, but a newly created gif0 interface has "mtu 1280", why would the default be so low? A second question. If the gif and gre tunnels will be wrapped in IPSec transport mode, does it make sense to set the MTU on the corresponding gif and gre interfaces to some lower value? -- Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJeeEJcAAoJEA2k8lmbXsY0L7gH/28dlW0TzJvrYCimZPgvq9UP X4/ur29r5M0IH4WldQfSIm1uoMjB7I4LallXU12K27RTsZcXwUBwHzjINaWMsNbi Jj1b1bAA0DdiDCLQeeJ1nWSMX/GYRq2cd9NR/AFJ8SQyZQxoiCk7OcRkwbc7eS9p FQ9Cqf/oBaEGcgtjUOcHs+Ahv1EM4nFF1qkgdXsGiCrugQ7nr9yt2ZI/3SCui+e8 H3bFqgYfE1El0skJ9kYNlv1vC5XpKvwXGdIy5l22ZTZ1igueajDr9V3L79ObIluI nVHiieTSaDewhVJgthhAGj4pF8BkeDyk0xwnHEMGlbDLm6trvKYgfDYPViALm68= =21Ty -----END PGP SIGNATURE-----help
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