{"id":2584,"date":"2018-11-09T02:21:24","date_gmt":"2018-11-09T02:21:24","guid":{"rendered":"http:\/\/www.mtin.net\/blog\/?p=2584"},"modified":"2018-11-09T02:21:24","modified_gmt":"2018-11-09T02:21:24","slug":"tech-tip-determining-mtu-via-macosx-ping-oh-yeah-and-windows","status":"publish","type":"post","link":"http:\/\/www.mtin.net\/blog\/tech-tip-determining-mtu-via-macosx-ping-oh-yeah-and-windows\/","title":{"rendered":"Tech Tip: Determining MTU via MacOSX Ping oh yeah and Windows"},"content":{"rendered":"

The command:
\nping -D -s\u00a01472<\/p>\n

What the command does
\nping = Obvious
\n-D = Don’t fragment
\n-s <value> = the ping size.<\/p>\n

Why did I start with 1472? That is the total packet size plus 28 bytes, which equals a 1500 byte packet.<\/p>\n

Example Output:<\/p>\n

Justins-MacBook-Pro:~ j2sw$ ping -D -s 1472 4.2.2.2\r\n<\/span>PING 4.2.2.2 (4.2.2.2): 1472 data bytes\r\n<\/span>1480 bytes from 4.2.2.2: icmp_seq=0 ttl=57 time=426.164 ms\r\n<\/span>1480 bytes from 4.2.2.2: icmp_seq=1 ttl=57 time=110.762 ms<\/span>\r\n\r\n--- 4.2.2.2 ping statistics ---\r\n<\/span>2 packets transmitted, 2 packets received, 0.0% packet loss\r\nround-trip min\/avg\/max\/stddev = 110.762\/268.463\/426.164\/157.701 ms<\/span>\r\n\r\nJustins-MacBook-Pro:~ j2sw$ ping -D -s 1473 4.2.2.2<\/span>\r\n\r\nPING 4.2.2.2 (4.2.2.2): 1473 data bytes\r\n<\/span>ping: sendto: Message too long\r\n<\/span>ping: sendto: Message too long\r\nRequest timeout for icmp_seq 0<\/span><\/pre>\n
If you want to learn how to do this on windows:
\nhttps:\/\/kb.netgear.com\/19863\/Ping-Test-to-determine-Optimal-MTU-Size-on-Router<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
The command: ping -D -s\u00a01472 What the command does ping = Obvious -D = Don’t fragment -s <value> = the ping size. Why did I start with 1472? That is the total packet size plus 28 bytes, which equals a 1500 byte packet. Example Output: Justins-MacBook-Pro:~ j2sw$ ping -D -s 1472 4.2.2.2 PING 4.2.2.2 (4.2.2.2): […]<\/p>\n","protected":false},"author":1,"featured_media":1501,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[17],"tags":[411,648,50,650,649],"jetpack_publicize_connections":[],"aioseo_notices":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.mtin.net\/blog\/wp-content\/uploads\/2017\/01\/ethernet.jpeg?fit=1800%2C1162","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6VLMf-FG","jetpack-related-posts":[{"id":76,"url":"http:\/\/www.mtin.net\/blog\/mikrotik-6-16-and-6-17-released\/","url_meta":{"origin":2584,"position":0},"title":"Mikrotik 6.16 and 6.17 Released","author":"j2sw","date":"July 20, 2014","format":false,"excerpt":"From the ChangeLogs What's new in 6.17 (2014-Jul-18 15:14): *) CCR1009 - fixed crash, only affects CCR1009; What's new in 6.16 (2014-Jul-17 13:12): *) 802.11ac support added in wireless-fp package for QCA9880\/9882 rev2 (-BR4A) chips; *) ip cloud now allows to set which IP to use - detected (public) or\u2026","rel":"","context":"In "Mikrotik"","block_context":{"text":"Mikrotik","link":"http:\/\/www.mtin.net\/blog\/category\/mikrotik\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1499,"url":"http:\/\/www.mtin.net\/blog\/ethernet-mtu-and-overhead\/","url_meta":{"origin":2584,"position":1},"title":"ethernet MTU and overhead","author":"j2sw","date":"January 8, 2017","format":false,"excerpt":"One of the most common questions is how much overhead do I need to account for on my transport network? 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